Vitamin D also known as Sunshine vitamin is produced in the body when our skin is exposed to sunlight. Its deficiency leads to a disease in which bone tissue doesn't properly mineralize leading to soft bones. The vitamin D deficiency disease in adults is known as Hypovitaminosis D.
The movement of blood in the body is called blood flow. The blood flows through the vessels, tissues and organs. Blood flow to a tissue will increase if the level of carbon dioxide at the tissue increases.
A sentence has been given in Direct/Indirect Speech. Out of the four given alternatives, select the one which best expresses the same sentence in Indirect/Direct Speech.