"It is very delicious."
大変 (たいへん) is used in negative sentences.
If you want to say something is good, delicious or something you wouldn't use たいへん.
Like a comment above me said, とても is more appropriate.
Or 超 (ちょう) if you want to use colloquial terms.
I say 超 more often but that's up to preference.
But it is very common to say たいへんよくできました.
I agree as a noun it is used as a negative. But as an adverb it does not have this restriction.
Notice the example たいへんおもしろい
Maybe it's similar to English phrases like "terribly fun", where a negative adjective becomes positive emphasis. :)
たいへん as a adjective means "serious, hard, difficult, terrible", but as an adverb it means "very, greatly". Despite it's meaning I don't know if it is also used with positive connotations. I think so.
Doesn't taihen have negative connotations? Wouldn't totemo be a more accurate translation?
I was looking for すごく as the "very" in this question. Its a common phrase すごく美味しいです
I think they didn't like the "それは," because they specified "it is." とてもおいしいです is accepted.
それは～です = it is, or that is. So anyone sees it again, please keep reporting.
I was thinking "hontou ni oishii desu." 本当においしいです。"It's really delicious." or "totemo oishii desu." with an emphasis on "totemo" とってもおいしいです！
I know enough Japanese to know to use "taihen" to answer this question, but it's so misleading for beginners and wouldn't be my first choice. It is often used as "difficult" for tests. Don't feel bad if you got it wrong. Geez....
とても wasn't given as an option despite appearing in the correct answer at the end.
How is 「多く」 （おおく） used? The dictionary says it can mean "mostly" and "a lot", but it was marked wrong in this sentence.
It is as an adverb or noun to indicate a large amount. Like 多く取れる can take a lot. 多くの場合 A lot of times.