Correct Answer  Option 4 : 50/3
Concept:
As per IS 456 Cl 23.2.1, deflection can be limited, by controlling the span to effective depth ratio as given in the following table.
Type of Beam

Span to effective depth ratio (basic) for span < 10m

If span > 10

Cantilever

7

These values should be multiplied by 10/span

Simply supported

20

Continuous

26

Calculation:
Given, Span = 12 m (> 10 m)
So, Span to effective depth ratio for a simply supported beam
\(\rm \dfrac{Span}{Effective \ depth}\) = 20 × \(\rm \dfrac{10}{span}\) = \(\dfrac{20\ \times\ 10}{12}\) = \(\dfrac{50}{3}\).
Hence, Span to effective depth ratio for a simply supported beam will be 50/3.