The diagram illustrates the human heart. After blood comes back from the lungs, in what sequence does it move through the chambers during one full circuit of the body?
- AQ $\rightarrow$ R $\rightarrow$ S $\rightarrow$ P
- BQ $\rightarrow$ R $\rightarrow$ P $\rightarrow$ S
- CP $\rightarrow$ S $\rightarrow$ Q $\rightarrow$ R
- DP $\rightarrow$ S $\rightarrow$ R $\rightarrow$ Q