Which of the Following Is NOT One of the Reasons

Which of the following is NOT one of the reasons planets around other stars are so difficult to detect?

A) planets don't give off their own light, but only reflect the light of their stars
B) planets are small compared to stars, and so don't have much surface area from which to reflect light
C) from far away, planets are typically lost in the glare of their parent star
D) planets have much less mass than stars
E) planets only form very late in the life of a star, just when it is ready to die, and thus last only a very short fraction of the star's life