What are the functionalities of the Sign Off and Exit buttons?

What are the functionalities of the Sign Off and Exit buttons?

A.
Sign Off helps the user change the branch whereas Exit logs the user out of the system.

B.
Exit helps the user change the branch whereas Sign Off logs the user out of the system.

C.
Sign Off helps the user log off a Module whereas Exit logs the user out of the system.

D.
Sign Off brings the user to the “sign on” screen whereas Exit logs the user out of the system.