In which sentence are parentheses correctly used?

A: South of Tokyo (beyond Yokohama) is the historic city of Kamakura.

B: South of Tokyo beyond Yokohama is the (historic) city of Kamakura.

C: South of Tokyo (beyond Yokohama is the historic city of Kamakura).

A: South of Tokyo (beyond Yokohama) is the historic city of Kamakura.