Mindy's Teachers Have Noticed That She Has Recently Shown Improvements

Mindy's teachers have noticed that she has recently shown improvements in abstract thinking, moral reasoning, decision-making, planning, inhibitory control, language, and problem solving. Regarding the changes in the brain during adolescence, Mindy's improved cognitive skills may be associated with

A) changes in gray matter.
B) a loss of myelin.
C) changes in white matter.
D) decreasing thickness of synapses.
E) increasing thickness of synapses.