Ethan is a manager at an advertising agency. His subordinates find him excessively assertive and energetic. Ethan constantly takes their attention away from their work by laughing loudly or joking around with them. He rarely sits at his desk. Instead, he constantly walks around the office premises socializing with other employees. In the context of personalities, Ethan can be described as being a(n) .
A) extravert
B) introvert
C) narcissist
D) mediator