Which of the following reactions occurs when $AgNO_3$ is heated above its melting point?

• A
  $2AgNO_3 \rightarrow 2Ag + 2NO_2 + O_2$
• B
  $2AgNO_3 \rightarrow 2Ag + N_2 + 3O_2$
• C
  $2AgNO_3 \rightarrow 2AgNO_2 + O_2$
• D
  $2AgNO_3 \rightarrow 2Ag + 2NO + 2O_2$