Which of the following systems use synchronous communication?

A. Skype video call

B. Facebook Chat

C. Email

D. Messaging on Snap chat

E. Telephone call

Choose the correct answer from the options given below:

The correct answer is A, B, D and E only.
Important Points

Synchronous communication refers to a mode of communication that happens in real-time, where people interact with each other simultaneously.

Based on the options given:

A. Skype video call: Yes, this is a form of synchronous communication. Participants engage in a conversation in real-time.

B. Facebook Chat: Yes, Facebook Chat also allows real-time, immediate interaction between users.

C. Email: No, email is asynchronous communication. The sender and recipient do not need to be available at the same time in order to communicate.

D. Messaging on Snapchat: It can be both. It can be synchronous if both parties are online and respond immediately to each other's messages. However, if the messages are not read and responded to immediately, it's asynchronous.

E. Telephone call: Yes, a telephone call is a classic example of synchronous communication. Both parties talk and listen in real time.

So, the correct answer would include Skype video call, Facebook Chat, possibly Snapchat messaging (depending on use), and telephone call. The option for your answer would depend on the choices given in your exam or quiz