It's c.
A. 42 1/2 pounds is way over. And if if she picked 4 1/4 pounds for $10, then your answer will be less than a 4 1/4.
B. It's too high, maybe for money it may work but not for a dollar.
C. It's the only that makes sense, and I did my work on paper and it is C.
D. It's way too high, just like B.