Answer
A
Work Step by Step
Since $[X]=n_X/V$, increasing the volume decreases the concentration of all species by the same factor, let's call it f > 1.
$Q=([NH_3]_0/f)^2/([N_2]_0/f)([H_2]_0/f)^3=f^4/f^2\times[NH_3]_0/[N_2]_0[NH_3]_0=K.f^2$
Since Q>K, the equilibrium shifts to the left.