At a Certain Temperature,K_c = 0

At a certain temperature,K_c = 0.0500 and △_rH° = +39.6 kJ for the reaction below.
2 MgCl₂(s) + O₂(g) ⇌ 2 MgO(s) + 2 Cl₂(g)
Calculate K_c for the reaction
MgO(s) + Cl₂(g) ⇌ MgCl₂(s) + 1/2 O₂(g)
And indicate whether its value will be larger or smaller at a lower temperature.

A) 4.47,larger
B) 400,smaller
C) 0.224,larger
D) 0.224,smaller
E) 0.0025,smaller