If X is a Poisson variate such that $ P(2)=9\: P(4)+90\: P(6)$. then mean of X is

Question

$\begin {array} {1 1} (A)\;\pm\: 1 & \quad (B)\;\pm\: 2 \\ (C)\;\pm\: 3 & \quad (D)\;None\: of \: these \end {array}$