Two friends work at different buildings on opposite sides of the city. They would like to meet for coffee after work someplace in between both locations. One friend works 9 blocks west and 6 blocks south of the center of town. The other friend works 9 blocks east and 4 blocks north of the center of town. Which restaurant is closest to the midpoint of the two locations?
A. Restaurant Casa, which is 1 block south of the center of town
B. Pizza di Franco, which is 9 blocks north and 5 blocks west of the center of town
C. Cafe Rosa, which is 2 blocks north and 2 blocks east of the center of town
D. 7th St. Market, which is 2 blocks south and 3 blocks east of the center of town