The diagrams present cross-sections of three blood vessels, and they are not to scale. Vessel 3 contains some red blood cells. In what sequence will red blood cells pass through these vessels as they move from the right ventricle to the left atrium of the heart?
- A$1 \rightarrow 2 \rightarrow 3$
- B$1 \rightarrow 3 \rightarrow 2$
- C$2 \rightarrow 3 \rightarrow 1$
- D$3 \rightarrow 1 \rightarrow 2$