The question simply is, which could be reduced by Cu?

Sn2+ (superscript 2+)

Ag+ (superscript +)

Zn2+ (superscript 2+)

 

How do i figure this out? ...by using some sort of database?

I know copper will spontaneously reduce Ag+

Not sure about the other 2.

You need a table of standard electrode potentials, but in this case it will reduce only silver ions

use your electrochemical series young skywalker,

or alternatively put your question in the homework forums.