Which species is oxidized in the following reaction?

$${\text{2A}}{{\text{g}}^ + }{\text{(aq)}} + {\text{Cu(s)}} \to {\text{2Ag(s)}} + {\text{C}}{{\text{u}}^{2 + }}{\text{(aq)}}$$

A.     ${\text{A}}{{\text{g}}^ + }$

B.     Cu

C.     Ag

D.     ${\text{C}}{{\text{u}}^{2 + }}$

B