I think it's B, but we can have a debate.
Okay, let's narrow this down:
First, read the problem carefully.
Now, we eliminate.
Choice D is wrong since it reflects of the whole U.S., not New Jersey.
Choice C is wrong since it reflects on STUDENTS at this public university in New Jersey.
Now we are down to A and B.
To me, I think it's B since it has a larger sample size, and it will have more accurate results.
I don't know why, either. I got B.