The reaction A(s)→2B(g)+C(g) is first order. The pressure after 20 min and after very long time are 150 mm Hg and 225 mm Hg. The value of rate constant and pressure after 40 min are :
(a) 0.05ln1.5 min−1 , 200 mm
(b) 0.5ln2 min−1 , 300 mm
(c) 0.05ln3 min−1 , 300 mm
(d) 0.05ln3 min−1 , 200 mm