The magnifying power of a compound microscope can be increased by

The correct option is B Using both lenses of smaller focal length
Correct answer is (c)

The magnifying power of a compound microscope is the ratio of the angle subtended at the eye by the image as seen through the lens to the angle subtended by the object at the unaided eye, when both are placed at the least distance of distinct vision, it is denoted by M.

So, by using the lenses of smaller focal length magnifying power of microscope can be increased.