Nerve Impulses Travel More Slowly in Babies Than in Older

Nerve impulses travel more slowly in babies than in older children and adults because:

A) an infant does not have as many synaptic connections as an adult has.
B) dendrites and axons take time to develop in infants.
C) neurons are much shorter in infants than in adults.
D) the myelin sheaths on axons are not yet fully developed in infants.