A car is fitted with a convex side-view mirror of focal length 20cm. A second car 2.8m behind the first car is overtaking the first car at a relative speed of 15ms–1. The speed of the image of the second car as seen in the mirror of the first one is
(a) 1/10ms−1
(b)1/15ms−1
(c) 10ms−1
(d) 15ms−1