The diagrams display cross-sections of three different kinds of blood vessel. They are not shown to the same scale. In what sequence will red blood cells pass through these vessels in the human body as they move from the aorta to the right atrium of the heart?
- A$1 \rightarrow 2 \rightarrow 3$
- B$1 \rightarrow 3 \rightarrow 2$
- C$2 \rightarrow 3 \rightarrow 1$
- D$3 \rightarrow 1 \rightarrow 2$