A seven-year-old child is rushed into the emergency room after being stung by a yellow jacket. The child is nauseated and vomiting and is experiencing itching and swelling on the arm where stung. The child is having trouble breathing. Which type of response is the child experiencing?

Choice A rationale Anaphylaxis is a severe, life-threatening, systemic hypersensitivity reaction (Type I) to an antigen, such as insect venom, characterized by rapid onset of symptoms like generalized itching, vomiting, and, most critically, respiratory distress due to laryngeal edema or bronchospasm. Choice B rationale An autoimmune response occurs when the immune system mistakenly attacks the body's own healthy tissues, which is a chronic process and is not the acute, immediate reaction observed after an external trigger like an insect sting. Choice C rationale Immunodeficiency refers to a state where the immune system's ability to fight infectious diseases or cancer is compromised, which increases susceptibility to infections but does not describe the acute allergic reaction to an external substance. Choice D rationale Active immunity is the long-term protection developed by the body's own immune system following exposure to an antigen or through vaccination, and it describes the state of immune protection, not the acute hypersensitivity reaction experienced by the child.