A person is to count 4500 currency notes. Let an denotes the number of notes he counts in the nth minute. If a1 = a2 = ............a10 = 150 and a10, a11...........are in A.P with common difference – 2, then the time taken by him to count all notes is
(a) 24 min
(b) 34 min
(c) 125 min
(d) 135 min