I'm taking an Audio class and my teacher gave us a 20 question pre-test. I figured out all but 1, and even though this doesn't have to be completed its driving me crazy. The question is- "The compressor’s side chain input can be used in a number ways to make
different things happen. If you parallel a signal to the compressor’s
program input and also to an equalizer and then to the sidechain input, the
compressor becomes:
o A Limiter.
o A De-esser.
o Variable gain amplifier.
o A tube amplifier.

If anyone knows the answer to this I would really appreciate it.