Correct answer is (c) 0.9fuAnf/γm1 ≥ fyAgf/γm0
Easiest explanation: IS 800 permits bolt holes in the flanges to be ignored when the tensile fracture strength of flange is at least equal to tensile yield strength i.e. when 0.9fuAnf/γm1 ≥ fyAgf/γm0 or (Anf/Agf) ≥ (fy/fu)x(γm1 /γm0)x(1/0.9), where Anf/Agf = ratio of net area to gross area of tension flange, fy/fu = ratio of yield stress to ultimate stress of material, γm1 /γm0 = ratio of partial safety factors against ultimate stress to yield stress.