John is the network administrator of XSECURITY systems. His network was recently compromised. He analyzes the log files to investigate the attack. Take a look at the following Linux log file snippet. The hacker compromised and “owned” a Linux machine. What is the hacker trying to accomplish here?

A.
The hacker is attempting to compromise more machines on the network

B.
The hacker is planting a rootkit

C.
The hacker is running a buffer overflow exploit to lock down the system

D.
The hacker is trying to cover his tracks

Explanation:
By deleting temporary directories and emptying like bash_history that contains the last commands used with the bash shell he is trying to cover his tracks.