How Would a Researcher Attempt to Examine Experience-Expectant Brain Development

How would a researcher attempt to examine experience-expectant brain development?

A) A researcher would conduct tests of motor skill ability on infants.
B) A researcher would observe toddlers playing in a playground with a lot of equipment and toddlers in a playground with minimal equipment.
C) A researcher would do sensory deprivation research with animals to see what impact that had on abilities.
D) A researcher would put some animals in stimulating environments and some animals in deprived environments and measure brain size.