At a Certain Temperature,K_c Equals 1

At a certain temperature,K_c equals 1.40 × 10² M^-1 for the reaction:
2 CO(g) + O₂(g) ⇌ 2 CO₂(g)
If a 3.00 L flask contains 0.400 mol of CO₂ and 0.100 mol of O₂ at equilibrium,how many moles of CO are also present in the flask?

A) 0.555 mol
B) 0.185 mol
C) 0.107 mol
D) 0.0114 mol