Question #4 reads:

The floor area ratio for a suburban property is 2.0. The lot is 50 ft wide (parallel to the street) by 100 ft deep (perpendicular to the street). The required front setback is 10 ft, and the back and side setbacks are 5 ft. Which of the following building configurations may be constructed?

A. a two-story building that is 50 ft wide by 100 ft deep

B. a three-story building that is 40 ft wide by 80 feet deep

C. a three-story building that is 40 ft wide by 85 ft deep

D. a four-story building that is 40 ft wide by 65 ft deep

I did the math and picked answer C.

100'x50' = 5,000 sf (site), 5,000 sf x 2.0 (FAR) = 10,000 (bldg. sf), 10,000 sf / 3,400 = 2.9 stories = 3 stories

I rounded the 2.9 stories to 3 stories. Should you not round? I am a bit confused.

Why is it B?