How do you change a foreground process into a background process ?

A The simplest way to start a background process is to add an ampersand (&) at the end of the command

B The simplest way to start a background process is to add an nice command at the beginning of the foreground process command

C The simplest way to start a background process is to add an ampersand (&) at the beginning of the foreground process command

D The simplest way to start a background process is to add fg command at the beginning of the foreground process command