The initial rate for zero order reaction of the gaseous reaction $A(g)\rightarrow 4B(g)$ is $10^{-3}Msec^{-1}$. If the initial concentration of $A$ is $0.01\;M$ after $2\;sec$. Concentration of $B$ should be

Question

$\begin{array}{1 1}(a)\;0.002M&(b)\;0.001M\\(c)\;0.008M&(d)\;0.004M\end{array}$