The Light-Gathering Power of a Telescope Is Directly Proportional to

Multiple Choice

The light-gathering power of a telescope is directly proportional to

A) the area of the primary mirror or lens.
B) the focal length of the primary mirror or lens.
C) the ratio of the focal lengths of its primary mirror or lens and its eyepiece.
D) the length of the telescope tube.
E) the diameter of the eyepiece.