What is the disadvantage of using the command kill -9 ?

A.
A core dump file will be created.

B.
It affects the entire process group.

C.
It makes excessive use of system resources.

D.
The action can be blocked by buggy or malicious processes.

E.
The affected process is unable to clean up before exiting.

Explanation/Reference:
From wikipedia: When sent to a program, SIGKILL (9) causes it to terminate immediately. In contrast to SIGTERM and SIGINT, this signal cannot be caught or ignored, and the receiving process cannot perform any clean-up upon receiving this signal.