The correct option is D Cocaine prevents reuptake of dopamine, increasing the dopamine activity in the synaptic cleft.
Cocaine acts as a psychoactive drug by blocking the activity of the dopamine reuptake transporter. When this transporter is inactivated, dopamine is not cleared away from the synaptic cleft after it stimulates the postsynaptic neuron. Thus the dopamine present in the synapse repeatedly stimulates the postsynaptic neuron, causing a stimulation of the neurons in the brains reward system.