When an electric current of $0.5\;ampere$ passed through acidulated water for two hours then volume of hydrogen $(H_2)$ at $NTP$ produced at cathode will be.

Question

$\begin{array}{1 1}0.1\;litre \\ 0.6\;litre \\ 0.4\;litre \\ 0.8\;litre \end{array}$