Answer:
b. Opening an umbrella on a beautiful day.
Step-by-step explanation:
A breaching experiment refers to an experiment in which the commonly accepted rules of the society are violated and the reactions of the people are taken into consideration. The common activities are breached and violated to build a better understanding of them. It is a study which helps in the study the social behavior in a larger perspective. Opening an umbrella on a beautiful day is an example of the breaching experiment while the other three options are not.