What is the difference between synchronous and asynchronous interactions?

A) Synchronous don't require all the participants to respond immediately;asynchronous occur in real time.
B) Synchronous occur in real time;asynchronous don't require all the participants to respond immediately.
C) Synchronous require social media;asynchronous require traditional media.
D) Synchronous require traditional media;asynchronous require social media.
E) Synchronous require mass media;asynchronous require personal media.