The reaction of an element $A$ with water produces a combustible gas $B$ and an aqueous solution of $C.$ When another substance $D$ reacts with this solution $C,$ it also produces the same gas $B.$ $D$ also produces the same gas even on reaction with dilute $H_2SO_4$ at room temperature. Element $A$ imparts a golden yellow color to the Bunsen flame. Then,$A, B, C,$ and $D$ may be identified as:

• A
  $Na, H_2, NaOH$ and $Zn$
• B
  $K, H_2, KOH$ and $Zn$
• C
  $K, H_2, NaOH$ and $Zn$
• D
  $Ca, H_2, Ca(OH)_2$ and $Zn$