The correct option is C Neutrophils
Neutrophils are normally found in the bloodstream and are the most abundant type of phagocyte, constituting 50% to 70% of the total circulating white blood cells whereas basophils (0.5%), eosinophils (1.5%) and Monocytes(4-8%). One litre of human blood contains about five billion neutrophils. Thus, the correct answer is option C.