A Simply Supported Steel Beam of Length L = 1 $(h=75 \mathrm{~mm}, b=20 \mathrm{~mm})$

A simply supported steel beam of length L = 1.5 m and rectangu- lar cross section $(h=75 \mathrm{~mm}, b=20 \mathrm{~mm})$ carries a uniform load of
Q = 48 kN/m that includes its own weight. The maximum transverse
Shear stress on the cross section at 0.25 m from the left support is approx-
Imately: (A) $20 \mathrm{MPa}$
(B) $24 \mathrm{MPa}$
(C) $30 \mathrm{MPa}$
(D) $36 \mathrm{MPa}$