​Pierre Performs a Maneuver with His Yo-Yo Called "Around the World",where

Multiple Choice

​Pierre performs a maneuver with his yo-yo called "around the world",where he swings the yo-yo in a vertical circle.When the yo-yo is at its highest point,which forces provide the centripetal acceleration?

A) ​friction
B) ​gravity
C) ​normal force
D) ​tension
E) ​Two of the above choices are correct.