The anterior surface of the heart consists mostly of this chamber.

It is one of the most vital part of the human body, as it operates as the pumping organ for the human body. There are three main surfaces of hearts structure which makes up the basic structural unit of the heart's body.

As the three surfaces of the heart structures, which are as below:

Explanation:

Sternocostal or the anterior surface:

The right atrium and right ventricle makes the anterior surface of the heart.They basically operates in the heart in order to receive the de-oxygenated blood from the whole body, and then sending the blood towards the lungs for its filtration. As the CO₂ level of the blood increases and it becomes less oxygenated in total, which then needs to be treated well.

Steps followed by both the chambers are as follows:

The heart receives the de-oxygenated blood from all across the body through the two different openings inside the blood circulatory system, which are:

The de-oxygenated amount of blood present in the right atrium of the heart is sent to the right ventricle which is then sent towards the pulmonary artery, inside the blood circulatory system. As the blood filtration is taken place on molecular level inside the lungs, as the CO₂ is removed from the molecule and then O₂ is aided to the blood medium which is again received by the heart and sent to the whole body.

i believe the answer would be b. hope it : )