List I: Component	List II: Function
(a) Neutrophils	(iii) Phagocytic action
(b) Immunoglobulins	(iv) Antibody action
(c) NK (Natural Killer) cells	(ii) Cytotoxic action
(d) $CD_4$ (T-Helper cells)	(i) Field Marshalls

Correct option is C

Neutrophils are phagocytic cells that engulf and destroy pathogens through phagocytosis, making them critical first responders in innate immunity. Immunoglobins (antibodies) perform antibody action by binding to antigens and marking them for destruction. NK (Natural Killer) cells exhibit cytotoxic action by directly killing virus-infected and cancerous cells without prior sensitization. CD₄ T-helper cells act as "Field Marshalls" of the immune system, coordinating and regulating immune responses by activating other immune cells.

Information Booster:
● Neutrophils constitute 50-70% of circulating white blood cells and are the first immune cells to arrive at infection sites through chemotaxis.
● Immunoglobins include five classes (IgG, IgM, IgA, IgE, IgD), each with specialized antibody functions in humoral immunity.
● NK cells are part of the innate immune system and recognize stressed cells through surface receptors, destroying them via perforin and granzyme release.
● CD₄ T-cells are crucial for adaptive immunity, and their depletion (as in HIV/AIDS) severely compromises immune function.
● The psychoneuroimmunology field studies how psychological stress impacts these immune components and overall health.
● Understanding immune system components is essential for studying stress-related immunosuppression and psychosomatic disorders.