1 mole of 'A', 1.5 mole of 'B' and 2 mole of 'C' are taken in a vessel of volume one litre. At equilibrium concentration of 'C' is 0.5 mole/L. Equilibrium constant for the reaction, A(g)+B(g)⇌C(g) is:
A. 0.66
B. 0.066
C. 66
D. 6.6