after the sun sets it continues to move further below the horizon,
reaching a maximum destance below the horizon around midnight.  Civil
twilight is the time between sunset and when the sun moves to six
degrees below the horizon.  Given what you know about the path the sun
takes through the sky, at what latitude would you generally expect
civil twilight to be the shortest? explain your reasoning?

This sounds like a homework assignment that anyone who had paid
attention or read the assignment should be able to answer immediately.
 Furthermore, anyone who can find G-A should very easily be able to
find the answer on the web.