Four Stores Have a Problem with Theft and Security Is

Multiple Choice

Four stores have a problem with theft and security is a public good. Let S stand for the number of personhours of security patrols per week. The marginal benefit of security patrols to each of the stores is given by the formula . Patrols cost $25 per hour. What is the socially efficient level of security?

A) 15 person-hours of patrols per week
B) 7 person-hours of patrols per week
C) 8 person-hours of patrols per week
D) 16 person-hours of patrols per week