Answer:
3
Step-by-step explanation:
the rule is if its .5 or higher than you round up. since the decimal in 2.664 is .664, you'd round up to make 3
I would say C.
A and B make no sense, you want to divide the group randomly because you want to test the new medicine. D is a bit more logical than A and B but still can't, because that isn't random.
It proves The function f(x) is an arithmetic sequence.