pulsars. quasars. supernovas. binary stars.
I gave my students this multiple choice question: Astronomers have been studying objects that are very bright and appear to be very far away. They have since concluded that these objects are distant galaxies with giant black holes at their center known as

Only one answer is correct among these 4 choices:
- pulsars.
- quasars.
- supernovas.
- binary stars.

Could you tell me which one is correct?

quasars.