What is the best operating system for hacking?

The fact is that hacking can be dine from any operating system but since most operating systems are designed to serve different purpose, hacking tools are designed for operating systems that are designed to serve hacking like Linux. 

Linux is open source and different parties has come up with different operating system from the Linux os that serve different purpose.

1. Parot os is designed to serve computer security like penetration testing, vulnerability, assessment and mitigation.
2. Kali Linux is designed to serve advanced penetration testing and security auditing like penetration testing, computer research, computer forensics and revers engineering.
3. Backtrack is used to test network, devices and system for security vulnerabilities.

The above operating systems are the commonly used.