Correct Answer - Option 2 :
\(\frac{{0.85\;bd}}{{{f_y}}}\)
Explanation:
Tension reinforcement (As per IS 456: 2000, clause 26.5.1.1):
The minimum area of tension reinforcement should be governed by
\(\frac{{{A_s}}}{{bd}}\; = \frac{{0.85}}{{{f_y}}} \Rightarrow {A_s} = \frac{{0.85 \times bd}}{{{f_y}}}\)
where As = minimum area of tension reinforcement,
b = breadth of rectangular beam or breadth of web of T-beam,
d = effective depth of beam,
fy = characteristic strength of reinforcement in N/mm2
The maximum area of tension reinforcement shall not exceed 0.04 bD,
where D is the overall depth of the beam.