The correct answer is B) The brain send signals to the blood vessels in the legs to dilate so that there is increased blood flow.
During running Tavi's muscles need oxygen to break down fats and carbohydrates for energy. As we know that blood work as carrier for oxygen so to make room for fresh oxygen, the brain send signals to the blood vessels to dilate to increase the flow of blood in legs. The process of dilation of vessels in our body is called vasodilation.