Which of these is a good definition for cyber threat hunting?

$1$ point

The act of detecting, investigating, and responding to incidents, including planning and implementing preventative security measures building disaster recovery plans

The act of simulating attacks to identify vulnerabilities, testing new software to help protect the company's data, and helping users adhere to new regulations and processes to ensure the network stays safe

The act of creating and maintaining corporate security structures and ensuring that they function as designed As high$-$level leaders, they also supervise security teams and have a hand in creating security$-$related policies and procedures

The act of proactively and aggressively identifying, intercepting, tracking, investigating and eliminating cyber adversaries as early as possible in the cyber kill chain