Final answer:
Allergies occur when the immune system has a hypersensitive reaction and causes a major inflammatory response to common environmental substances known as allergens option (c). This process is known as a Type I hypersensitivity, involving the sensitization of mast cells with IgE antibodies and leading to allergic reactions.
Step-by-step explanation:
The occurrence due to hypersensitivity in the immune system that causes a major inflammatory response to a common material is known as allergies. Allergies involve an exaggerated immune response to environmental substances, or allergens, that are generally not harmful.
The immune system mistakenly identifies these substances as dangerous and mounts an attack which results in various symptoms.
Allergies are a Type I hypersensitivity, which requires sensitization of mast cells with IgE antibodies. Upon subsequent exposure to the same allergen, these antibodies cause mast cells to release histamine and other chemicals, leading to an allergic reaction.
Unlike autoimmune disorders or immunodeficiencies, allergies involve a hyperactive immune response against benign antigens from the environment.