Answer:
Option C, right atrium --> right ventricle --> pulmonary artery
Explanation:
The flow of blood on the right side includes the following
a) The inferior and superior vena cava carrying the oxygen deficient blood, empties the blood into the Right Atrium
b) From the right atrium, the blood flows into the right ventricle and the tricuspid valve prevents the back flow of blood into atria.
c) The blood then drains into the pulmonary artery through the pulmonic valve
Hence, the correct order of blood flow is option C
