All of the veins of the systemic circulation drain into the before returning to the heart.
a. pulmonary trunk
b. superior and inferior vena cavae
c. inferior vena cava
d. pulmonary veins
e. superior vena cava

Option B

Explanation:

All the blood from the body gets pure inside the heart. The impure blood from the body is collected by the superior vena cavae and inferior vena cavae.

The waste blood from the body is collected and enters collectively into the heart. This blood is impure(deoxygenated)  and need to be pure (oxygenated) before being circulated into the body.

So, the correct answer is option B

The theme of the story ‘Man in the well’ emphasizes the terrible behavior of children to adults who are in danger. The children, when they are in a group, act strangely and forgive lesser. They do not understand if adults are in danger.

The questions asked by the children to the man struck inside a well, instead of helping him clearly states that the children can be strange and terrible. Also, the man in the well exposes his fear by shouting and using harsh voices at children. His scary behavior might also be a reason for the children to not help him.