At High Temperatures, Carbon Reacts with O₂ to Produce CO

Multiple Choice

At high temperatures, carbon reacts with O₂ to produce CO as follows: C(s) + O₂(g)
2CO(g) .
When 0.350 mol of O₂ and excess carbon were placed in a 5.00-L container and heated, the equilibrium concentration of CO was found to be 0.060 M. What is the equilibrium constant, K_c, for this reaction?

A) 0.010
B) 0.072
C) 0.090
D) 0.17
E) 1.2