Solve the Problem. Round Your Answer, If Appropriate

Solve the problem. Round your answer, if appropriate.
-As the zoom lens in a camera moves in and out, the size of the rectangular image changes. Assume that the current image is 4 cm × 3 cm. Find the rate at which the area of the image is changing (dA/df) if the length of the image is changing at 0.6 cm/s and the width of the image is changing at 0.2 cm/s.

A) 6.0 /sec
B) 2.6 /sec
C) 3.0 /sec
D) 5.2 /sec