What Is the Chief Difficulty in Attempting to Detect Planets

Multiple Choice

What is the chief difficulty in attempting to detect planets around other stars?

A) Even the largest planets are typically at least a factor of 10 times smaller than their host stars.
B) Planets do not emit visible light. They are typically at least a billion times fainter than their host stars.
C) Planets do not glow in the infrared, so infrared telescopes cannot be used to study them, either.
D) A and B
E) A, B, and C