耳 works English to Japanese translations. This question requires the English translation.
If it was a listening exercise you mean: those are auto-generated and are incapable of accepting more than a single 'best' answer. Since this is from the hiragana skill, the hiragana is required for those.
I learned this word when watching "the last samurai." I didnt have subtitles so i eneded up watching half the movie in japanese making assumptions on what they were saying. Despite taking japanese in middle school i didn't really understand what they were saying, but when the little boy pulled on his ears and said "mimi!" I knew that meant ear, and thats how i remember mimi.
If it is a native Japanese name there will probably be set of kanji for it, though stylistically they may choose to write it in hiragana.
耳・みみ means "ear", but a person's name can be written with any "mi" pronounced kanji, such as 美美, 佳美, 海々, 光海, 光美, 三弥, 実心, 実瞳, etc. (Jisho lists 202 different spellings of the name)
If the name is foreign it would be written in katakana ミミ