Bottles containing $C_6H_5I$ and $C_6H_5CH_2I$ lost their original labels. They were labelled $A$ and $B$ for testing. $A$ and $B$ were separately taken in test tubes and boiled with $NaOH$ solution. The end solution in each tube was made acidic with dilute $HNO_3$ and then some $AgNO_3$ solution was added. Substance $B$ gave a yellow precipitate. Which one of the following statements is true for this experiment?

• A
  $A$ was $C_6H_5I$
• B
  $A$ was $C_6H_5CH_2I$
• C
  $B$ was $C_6H_5I$
• D
  Addition of $HNO_3$ was unnecessary