The equilibrium constants Kp1 and KP2 for the reactions X ⇋ 2Y and Z ⇋ P + Q, respectively are in the ratio of 1 : 9. If degree of dissociation of X and Z be equal then the ratio of total pressures at these equilibria is
(a) 1 : 9
(b) 1 : 36
(c) 1 : 1
(d) 1 : 3
