How does the mammalian body protect itself against infections​

The body defends against infection by increasing the number of certain types of white blood cells (neutrophils and monocytes), which engulf and destroy invading microorganisms. The increase can occur within several hours, largely because white blood cells are released from the bone marrow, where they are made.

answer: b

coz red blood cells marrow and circulates the body for 120 days.