A. Present Perfect Continuous: We are interested in the activity. It does not matter whether something has been finished or not.
A1. Present Perfect Simple: We are interested in the result (not activity itself). The important thing is that something has been finished.
B. use the Continuous to say how long (for an activity that is still happening)
B1. use the Simple to say how much, how many or how many times (for completed actions)
C. not normally used in the continuous: know/ like/ believe
C1. can use want and mean in the Present Perfect Continuous, but not in the Present Continuous.