At 400ºC,K_c = 64 for the Equilibrium H₂(g)+ I₂(g)

At 400ºC,K_c = 64 for the equilibrium H₂(g) + I₂(g) 2HI(g) .If 3.00 mol H₂ and 3.00 mol I₂ are introduced into an empty 4.0-L vessel,what is the equilibrium concentration of HI at 400ºC?

A) 0.15 M
B) 1.2 M
C) 2.4 M
D) 4.8 M
E) 5.8 M