balanced chemical reaction vs. equilibrium constant expression?

Question

Write the balanced chemical reaction which corresponds to the following equilibrium constant expression.
K = (PCO2)2/(PCO)(PO)

Answer 1

The expression cannot be correct, because that would correlate to:

CO + O <---> 2 CO2

which is not balanced.

The balanced reaction for carbon monoxide reacting with oxygen to form carbon dioxide is:

2 CO + O2 <---> 2 CO2

for which the Kp expression is:

Kp = P(CO2)^2 / P(CO)^2 P(O2)

Answer 2

Keq = [NH3]^2 / {[N2][H2]^3} The last choice