A : Transmission of the nerve impulse across a synapse is accomplished by neurotransmitters .
R : Transmission across a synapse usually requires neuro transmitters because there is space , i.e., synaptic cleft, that separates one neuron from another .
A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false