How Do Quasars Demonstrate That the Universe Evolves with Time

How do quasars demonstrate that the universe evolves with time?

A) there were very few quasars long ago, and their numbers have been growing since
B) quasars began emerging only about a billion years ago, and now there are many more than ever
C) quasars have been around since the big bang, but the radiation they give off gets stronger and stronger as time in the universe goes on
D) the number of quasars reached a maximum some time ago, and now the numbers have been declining
E) quasars actually don't demonstrate any evolution; the number of quasars has been pretty constant for the entire history of the universe