In His Research on Children's Reaching and Grasping, What Did

In his research on children's reaching and grasping, what did Halverson (1931) find?

A) His youngest subjects could not yet use their thumbs to oppose their fingers.
B) The position of the thumb during the reach often indicated the likelihood of the thumb being used to oppose the fingers.
C) A relatively specific progressive sequence of grasping behavior exists.
D) All of the above