Bailey Is an Infant Boy Who Is Sitting in His

Bailey is an infant boy who is sitting in his car seat. He is waving his hands around and his thumb accidentally touches his cheek. He turns his head toward his thumb and puts it into his mouth. He begins to suck on it and finds that he likes it. He quickly learns to put his thumb into his mouth and suck on it whenever he wants to. What sensorimotor substage does this illustrate?

A) secondary circular reactions
B) primary circular reactions
C) tertiary circular reactions
D) mental representations