Which of these activities will most likely impose an external cost? a. an athlete works out at a gym. b. a construction worker eats a hotdog during his lunch break. c. a young mother pushes her baby in a stroller. d. a secretary smokes a cigarette in a crowded break room.

 d. A secretary smokes a cigarette in a crowded break room.

Explanation:

An external costs can be define as the activity which is likely to disturb the nature or cause harm to a living being. d. is the correct option because of the fact that if the secretary smokes a cigarette the smoke likely to disturb the crowd in the break room as some people may feel suffocated because of the smoke due to obstruction of natural air in the nostrils.

answer; planning ahead;