Answer:
(B). an increase in the number of WBCs in the blood
Explanation:
WBCs or white blood cells are components of immune system that fight against a number of infection-causing agents, such as bacteria, fungi, and viruses. Examples of WBCs include neutrophils, basophils, monocytes, B lymphocytes, T lymphocytes and mast cells.
As these cells help to fight against infection, their number increases at the time of an infection. Hence, an elevated level of white blood cells is used as an indicator of a body infection.
Thus, the correct answer is option (B).
