A compound X when heated with NaOH solution produces a pungent gas that turns red litmus blue. When an aqueous solution of X is treated with $$\mathrm{AgNO_3}$$ solution, a white precipitate Y is obtained which on keeping in sunlight turns grey liberating pale yellowish green gas. The aqueous solution of compound X is

A

neutral

B

slightly acidic

C

slightly alkaline

D

strongly acidic