Answer is 7
Bcz when we execute fork() command then a child process is created and then the next instruction following this fork() command will be executed by both parent as well as by the child process.
First fork() will generate 1 children. Total number of process = 1 child (C1) + 1 parent (P) = 2.
Second fork() will generate 1 more process in C1 (C2) and one more process in P (C3), Total number of child processes at this stage = 3.
Similarly, 4 more child processes will be generated after calling third fork().
So, overall 8 processes will be there, 1 parent and 7 children.