In the Ceiling Zone Method of Distribution, the Usable Floor

In the ceiling zone method of distribution, the usable floor area should be divided into zones each measuring:

A) 9.3 sq m (100 sq ft) to 23 sq m (250 sq ft)
B) 23 sq m (250 sq ft) to 56 sq m (600 sq ft)
C) 23 sq m (250 sq ft) to 84 sq m (904 sq ft)
D) 56 sq m (600 sq ft) to 84 sq m (904 sq ft)
E) 56 sq m (600 sq ft) to 100 sq m (1,100 sq ft)