For the Reaction of Carbon with Carbon Dioxide to Make

For the reaction of carbon with carbon dioxide to make carbon monoxide, one set of conditions produced a K_c = 1.2 × 10^-1. At equilibrium at a certain temperature, the concentration of product was 0.60 M. What was the concentration of carbon dioxide at that temperature?
C(s) + CO₂(g) ⇌ 2CO(g)

A) 3.0 M
B) 0.60 M
C) 0.36 M
D) 3.33 M
E) 5.0 M