Which of the following expressions is the correct equilibrium-constant expression for the equilibrium shown?

Question

equilibrium reaction: 2 A (g)  B(g)

A. [A][B]

B.
C.
D.
E. [B]2[A]

Answer 1

2A(g) <==> B(g)

K = [B] / [A]²

Answer 2

question is not visible clearly so i will tell you can apply

Keq=[A]^n[B]^n/[c]^n [d]^n

where n is stochiometric coefficents