Coordination and response — practice question

The diagram illustrates a synapse within a reflex arc. Which two neurones are shown, and in what direction does the neurotransmitter move?

• Aneurone P motor, neurone Q relay, direction $P \rightarrow Q$
• Bneurone P motor, neurone Q sensory, direction $P \rightarrow Q$
• Cneurone P relay, neurone Q motor, direction $Q \rightarrow P$
• Dneurone P relay, neurone Q sensory, direction $Q \rightarrow P$