A car is fitted with a convex side-view mirror of focal length 20 cm. A second car 2.8m behind the first car is overtaking the first car at a relative speed of 15 m/s. The speed of the image of the second car as seen in the mrror of the first one is:
A. −115m/s
B. 10m/s
C. 15m/s
D. 110m/s