In general, synchronous communication means you have to wait for the answer all the time. The programming logic is simpler, but the cost that you spend a lot of time waiting.
If the options are:
<span>a. The people communicating don't need to be online at the same time.
b. There is lag time in the communication.
c. The communication occurs in real time.
a is false, you do need to be online to receive the message
b is true, typically you continue only after an acknowledgement
c is true, you wait for acknowledgement that occurs in real time (not necessarily fast though)</span>
