An R.C.C. roof slab is designed as a two way slab if
A. It supports live loads in both directions
B. The ratio of spans in two directions is less than 2
C. The slab is continuous over two supports
D. The slab is discontinuous at edges
Answer: Option B

The answer is B because when the long-to-short span ratio is less than 2, the slab deflects and transfers loads in both directions.