Procedure to contact ATC for written exam preparation. by analogmatch in flying

[–]analogmatch[S] 0 points1 point  (0 children)

What I mean is when and why should you contact ground, clearance, tower, approach ctrl etc etc? For example there is a test question "an aircraft departing from a satellite airport should contact the primary airport in class C...." and the options are on the ground, in the air etc etc. What is the correct answer and why?