The diagram illustrates the human heart. In what sequence does blood move through the chambers in a complete circuit of the body after it comes back from the lungs?
- 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