Jessica, 4 years old, is unwilling to wait until her birthday to open her gifts. What neural characteristic can explain why she is having difficulty delaying gratification?
a. Neurons in the prefrontal cortex are fully myelinated.
b. Neurons in the cerebellum are not fully myelinated.
c. Neurons in the prefrontal cortex are not fully myelinated.
d. Neurons in the thalamus are fully myelinated.