The given diagram shows blood circulation pathway in the heart. Which of the following correctly shows the relative amount of oxygen and carbon dioxide at P, Q, R and S?
AMore CO2 - R; More O2 - P, Q, S
BMore CO2 - Q and R; More O2 - P and S
CMore CO2 - S; More O2 - R
DMore CO2 - P and Q; More O2 - R and S
Explanation for this question