In the above chemical reaction,intermediate $X$ and reagent/condition $A$ are:

• A
  $X = \text{Benzene diazonium chloride}; A = H_2O/NaOH$
• B
  $X = \text{Nitrobenzene}; A = H_2O/\Delta$
• C
  $X = \text{Benzene diazonium chloride}; A = H_2O/\Delta$
• D
  $X = \text{Nitrobenzene}; A = H_2O/NaOH$