Which substance in this redox reaction is the oxidizing agent?

[tex]\[ \text{Cu} + 2 \text{AgNO}_3 \rightarrow 2 \text{Ag} + \text{Cu(NO}_3\text{)}_2 \][/tex]

A. [tex]\( \text{N} \)[/tex]
B. [tex]\( \text{AgNO}_3 \)[/tex]
C. [tex]\( \text{Cu} \)[/tex]
D. [tex]\( \text{NO}_3^- \)[/tex]
E. [tex]\( \text{Cu(NO}_3\text{)}_2 \)[/tex]