The correct option is D defence mechanisms of the body
Globulins in human blood plasma are primarily involved in defence mechanisms of the body. Globulins like immunoglobulins act as antibodies that destroy bacteria, viruses and toxic substances that may enter the blood from outside.
Electrolytes and non-electrolytes contribute to the osmotic balance.
Haemoglobin is the protein inside red blood cells that carries oxygen to cells.
Platelets, also called thrombocytes are a component of blood whose function (along with the coagulation factors) is to stop bleeding by clumping and clotting blood vessel injuries.