Number of ions present in 2.0 litre of a solution of $0.8MK_4Fe(CN)_6$ is

Question

$\begin{array}{1 1}(a)\;4.8\times 10^{22}&(b)\;4.8\times 10^{24}\\(c)\;9.6\times 10^{24}&(d)\;9.6\times 10^{22}\end{array}$