What is the primary role of basophils in the body?

Basophils play a crucial role in the immune system, particularly in the body's response to allergens and in inflammatory reactions. They are a type of white blood cell, specifically a granulocyte, and their primary function is to release histamine and other chemicals during immune responses.

Histamine is a key compound involved in allergic reactions, as it increases blood flow to affected tissues and makes the blood vessels more permeable, allowing other immune cells to access the site of an allergen. This response is part of the body's way of protecting itself, albeit sometimes excessively in cases of allergies.

In contrast, the other options describe functions that do not accurately reflect the role of basophils. Regulating blood pressure is primarily the function of the cardiovascular system influenced by various factors, while promoting blood clotting is managed by platelets and specific clotting factors. Transporting oxygen is the primary responsibility of red blood cells, which contain hemoglobin to facilitate this process. Thus, the correct choice highlights the essential role of basophils in mediating allergic responses and their involvement in the inflammatory process.