Identify $A$ and $B$ in the following reaction:
$C_2H_5Cl \xrightarrow{A} C_2H_5OH \xleftarrow{B} C_2H_5Cl$

• A
  $A = \text{aq. } KOH; B = AgOH$
• B
  $A = \text{al. } KOH / \Delta; B = \text{aq. } NaOH$
• C
  $A = \text{aq. } NaOH; B = AgNO_2$
• D
  $A = AgNO_2; B = KNO_2$