When a substance Areacts with water it produces a combustible gas B and a solution of substance C in water. When another substance D reacts with this solution of C, it also produces the same gas B on warming but D can produce gas B on reaction with dilute sulphuric acid at room temperature. A imparts a deep golden yellow colour to a smokeless flame of Bunsen burner. A, B, C and D respectively are

• A. \[Na,{{H}_{2}},NaOH,Zn\]
• B. \[K,{{H}_{2}},KOH,Al\]
• C. \[Ca,{{H}_{2}},Ca{{\left( OH \right)}_{2}},Sn\]
• D. \[Ca{{C}_{2}},{{C}_{2}}{{H}_{2}},Ca{{(OH)}_{2}},Fe\]