Which of following is the best example of a monopoly if we use a broader definition of​ monopoly?

A. Santos​ Tacos, the only taqueria in the small town of Santosville
B. Zippie​ Rentals, a car rental service in Boston
C. Cheap​ Gas, one of two gasoline stations in a large rural community
D. Spuds​ Mckenzie, a wealthy potato farmer in Idaho