Coordination and response — practice question

The diagram shows a simple reflex arc. What is the order of nerve cells through which an impulse travels during a reflex action?

• AP $\rightarrow$ Q $\rightarrow$ R
• BQ $\rightarrow$ R $\rightarrow$ P
• CQ $\rightarrow$ P $\rightarrow$ R
• DR $\rightarrow$ P $\rightarrow$ Q