Because White Dwarfs Are Small, as Their Name Implies, They

Because white dwarfs are small, as their name implies, they are hard to see. What is a way astronomers have to find white dwarfs that distinguishes them from main sequence stars?

A) because white dwarfs get really hot, we can search for their ultraviolet radiation
B) because white dwarfs all have planets around them, we can use the transit method to find them
C) because white dwarfs are making complex molecules in their outer regions, we can search for them with radio telescopes
D) all white dwarfs pulsate (they get brighter and dimmer) every few minutes and this regular change in brightness is easy to notice
E) there is no way to distinguish white dwarfs from other dim stars. That's why we only know two or three white dwarfs in the sky.
Section 23.2: The Evolution of Massive Stars: An Explosive Finish