The correct option is A allergy
Allergy is the exaggerated response of the immune system (IgE type antibodies released) to certain antigens such as pollen, dust, etc.
Auto-immunity is the the damage of self-cells by the body due to an abnormality. e.g : rheumatoid arthritis
Inflammation is the swelling and redness of an injured region of the body and is a response to tissue damage. It is always followed by repair.
Infection is a condition caused by a pathogen such as bacteria, fungi, etc. and is characterised by a fever. e.g : TB, UTI, etc