A friend of mine is an Assistant Language Teacher at a junior high school in Japan. The textbook for the grade eight class has the question "Is Eri's host family kind to her?"
If I were to answer that question, I would use a plural and say "Yes, they are." But the main teacher of the class says that the proper answer is "Yes, it is," because the question is asked in the singular form. This seems really unnatural to me.
Which of these is correct, and why? The main teacher will not be satisfied with anything other than an answer that's backed up with proper rules of grammar.