Which quality of a leader requires that he should understand people and maintain good human relations with them?

Social Skills

The correct answer is option 4- social skills.

A leader should have some skill to lead his followers-

* Integrity: A leader should posses high level of integrity and honesty. He should be a role model to others regarding the ethics and values. 
* Initiative: A leader should have courage and initiative. He should not wait for opportunities come to his way, rather he should grab the opportunity and use it to the advantage of organisation.
* Communication skills: A leader should be a good communicator. He should have the capacity to clearly explain his ideas and make the people to understand his ideas. He should be not only good speaker but a good listener, teacher, counsellor and persuader.
* Social skills: A leader should be sociable and friendly with his colleagues and followers. He should understand people and maintain good human relations with them.