In one study, 3-year-old children were asked to feel fabrics and say whether they were the same or different. What evidence indicated that the corpus callosum was immature in these children?

a. They made more errors at the start of a session than toward the end.

b. They made more errors toward the end of a session than at the start.

c. They made more errors when feeling with two hands than with one.

d. They made more errors when feeling with one hand than with two.