Translation:Kanji is very difficult.
Even though "kanji" can be a countable noun and refer to multiple individual characters, the way it's used in this sentence, I think of it as an uncountable noun, like "information".
Still, while "Kanji are very difficult" sounds funny to me in a way I find difficult to explain, I think it's valid.
Counterexamples: dogs (in general) are cute, mathematicians (in general) are lazy, rocks (in general) don't taste very good. It doesn't have anything to do with whether the noun is general, it has to do with whether the noun is countable. Since kanji is used as countable by some and uncountable by others, it should (and does) accept both versions.
Not accepted 10 Jan 2019... And with these listening questions, there is no "my answer should be accepted option"... So I just have to copy/paste the correct answer a million times, hoping that they have some internal metric of how often questions are incorrect... and after doing that for 10 minutes, I'll post what they're expecting to get it marked as complete.
That's a funny idea... Japanese comedians make use of homophones all the time for wordplay like that. However, for a case like "feelings are difficult", むずかしい feels odd. I'm not even sure it's possible at all, but 難しい感じ sounds more like they're troublesome or hard to express. If you really want to say "difficult to understand", you normally use 分かりにくい.
PS: the kanji for ~にくい is the same as that of むずかしい though: ~難い. It's a construction that can be added to any verb, to make it mean "difficult to X". E.g. 聞きにくい 'difficult to hear' or やりにくい 'difficult to do/pull off'. That makes for another fun pun, since the word for "ugly" is みにくい （醜い）, which sounds the same as 見にくい "difficult to see".
I wrote "Chinese characters are very difficult." and it didn't take it. 漢字 literally means "Chinese characters". It seems weird that it would want a transliteration.
Edit: Before you downvote me, maybe try looking up 漢字 and especially 漢 in a dictionary.
I'm very aware that the roumaji transliteration "kanji" can be used directly as an English word. It's just that when the goal is to actually translate stuff, just transliterating the words doesn't seem like the most likely expected response to me.
Knife, spoon and table (ナイフ、スプーン、タブル) are transliterations into Japanese despite other concise words (出刃、匙、表). Even if a dictionary says one thing, context is more important to understanding and translating.
After all, do you say "I want a pressed coffee from the coffee shop" or "I want an espresso from the café"?
Except that kanji are almost never called "Chinese characters" in English when referring to their use in Japanese. The Japanese word "kanji" has been borrowed into English. Translating 漢字 as "Chinese characters" would be like translating 東京 as Eastern Capital instead of as Tokyo
Of course even kanji invented in Japan and never used in China, such as 駅 are still called "kanji" but it seems odd to refer to them as "Chinese characters".
"Kanji" is simply a word that has multiple meanings. In English it means something like "Characters in written Japanese that are neither hiragana nor katakana and which either originated in China or mimicked Chinese characters". Or just "Chinese style characters as used in Japanese writing".
No Japanese words have a plural. But when they are borrowed into English they also become English words and then they may or may not gain English plurals: sushi did not gain a plural, futon did gain a plural.
I personally don't say "kanjis" and I even dislike it pluralized that way. But many people do in fact prefer to use it that way so I think both should be accepted despite my dislike. It's even in some dictionaries: https://en.wiktionary.org/wiki/kanjis
Nihongo is comprised of three symbol sets.
Kanji-originally symbols from Chuugoku representing nouns/ideas/feelings, which some meanings and readings for the characters have changed to be unique for Nippon.
Hiragana was originally made from Kanji by Nihonjin aristocrat women to write poetry, have their own langauge to express themselves as fems weren't allowed to use kanji at that time. Today hiragana is used for completely culturally Nihon nouns/ideas/feelings and sentence particals. Hiragana is the default, first taught in schools.
The katakana is used for foreign words and was based off hiragana.