Cu reduction question

Im having trouble with the following question as I missed it during class:

Of Sn 2+, Ag +, and/or Zn 2+, which could be reduced by Cu?

A. Ag+
B. Sn2+
C. Zn2+
D. All of them could be reduced by Cu.
E. Two of them could be reduced by Cu.

Thanks for help

Search for "voltaic series" in google.

A compound just able to reduce compounds located in its left side, while it can oxidize compounds located in its right side.

here's an example of voltaic series
Li K Ba Sr Ca Na Mg Al Mn Zn Cr Fe Cd Co Ni Sn Pb H Sb Bi Cu Hg Ag Pt Au

Sn and Zn located in left side of Cu --> they can be reduced by Cu
Ag located in the right side of Cu --> they can't be reduced by Cu, Cu will be reduced instead.