Question: A particle continuously moves in a circular path at constant speed in a counterclockwise direction. Consider a time interval during which the particle moves along this circular path from point P to point Q. Point Q is exactly half-way around the circle from Point P.What is the direction of the average velocity during this time interval? A) rightward  B) leftward  C) upward  D) The average velocity is zero. Please choose an answer from [A, B, C, D].
Answer: B