What is considered an extensive communication skill?

The correct answer would be Verbal Communication.

Explanation:

When someone is able to convey his message to the other person or group of persons, in a strong manner, with clear and unambiguous delivery of message, the person is said to have extra ordinary communication skills. There are different types of communications, like verbal, writing, gestures, facial, body, etc. The best way to communicate through the other person is through mouth. So verbal communication is considered to be the extensive communication skill among all others.