I need typing answer urgent

Which of the following transactions or interactions generate a positive or negative externality? If you identify an externality, succinctly state nature of the externality. If an externality does not exist, succinctly discuss your rationale for exclusion of an externality. a) An engineer builds a bridge b) Insurance Fraud ( ( (c) A medical doctor treats a patient (d) Government lowers taxes ( e) A cousin becomes state governor