The family who______ upstairs_____all model workers.

[嘟嘟嘟嘟]

1. The family who____________ upstairs_______ all model workers.
A. lives, are B. live, are
2. The class________ in the next room_______ Class 5.
A. that are , is B. who is, is C. which is, is
For the first one, the answer is B. Can't I say "the family who lives upstairs"?
For the second one, the answer is C, I can't understand why it is C. I think both A and B are OK except C.
Expecting for your opinions. Thanks!

 

[jutfrank]

1B
2C

In 1, it's much better to use family as a plural, because it goes with workers.
In 2, A is no good because it mixes singular and plural. B is no good because the class is not a person.