Wayne Is Asked to Look at Two Rows of M&Ms

Wayne is asked to look at two rows of M&Ms. The first row has five M&Ms all lined up and nearly touching. The second row has five M&Ms all lined up but spread out, thereby taking up much more room than the first row. When Wayne is asked which row has more M&Ms, he exclaims, "They both have the same amount!" According to Piaget, in which stage of cognitive development is Wayne?

A) either the sensorimotor stage OR the formal operations stage
B) the preoperational stage
C) either the concrete operations stage OR the preoperational stage
D) the sensorimotor stage