When babies are confronted with slopes, they may go down the slopes in a variety of ways, not in a single way. This outcome has been taken to show that

A) Motor development follows a rigid maturational progression
B) Motor development does not follow a rigid maturational progression
C) Developing a theory of motor development puts the theorist on a slippery slope that should be avoided
D) Developing a theory of motor development puts the theorist on a slippery slope that should not be avoided