For a first order reaction A → Products, the concentration of A changes from 0.1 M to 0.025 M in 40 minutes. The rate of reaction when the concentration of A is 0.01 M is
(a) 1.73 x 10-4 M min-1
(b) 1.73 x 10-5 M min-1
(c) 3.47 x 10-4 M min-1
(d) 3.47 x 10-5 M min-1
