"What date is it today?"
I agree. What is would be the literal translation of their answer? (今天几月几号)
I think it'd be "What day and month is today?" so the answer would include the month and wouldn't just be "The 17th".
In English, if you ask, "what's the date?" they would normally just say "the 17th".
In the exercise right before, what is correct for this problem was exactly wrong apparently...
It seems as though the further I go in this Chinese course, the less competent the Bird becomes. Sad.
If you are being pedantic it should be "jintian ji nian ji yue ji hao", but that is marked wrong