10 pts Consider three buildings in an office submarket. Building 1 has 450,000 SF of which 27,000 SF are vacant, Building 2 has 220,000 SF of which 59,400 SF are vacant, and Building 3 has 170,000 SF of which 30,600 SF are vacant. Based on this information, what is the vacancy rate using the simple average method? 16% O 17% 18% O 19% O 20%