Which of the following cells are called the 'soldiers of the body'?

White blood cells are cells of the immune system that protect the body against foreign bodies, including pathogens. These cells circulate throughout the body through the blood and help fight pathogens. Red blood cells have hemoglobin, which carries oxygen.

Platelets help clot blood  to stop bleeding from cuts.

Hence the correct option is (B) i.e, WBCs.