Correct Answer - Option 4 :
\(\frac{{3W{R^2}}}{{16}}\)
Radial moment at the centre of the Circular slab is
\({M_R} = \frac{W}{{16}} \times \left( {\left( {3 + \mu } \right)\left( {{R^2} - {r^2}} \right)} \right)\)
Where MR = Radial moment
R = radius of slab
μ = Poisson’s ratio
r = any section at a distance r from centre of the slab
W = load on circular slab
For maximum radial moment at centre
r = 0 and μ = 0
therefore, \({M_R}\; = \frac{W}{{16}} \times 3 \times {R^2} = \frac{{3W{R^2}}}{{16}}\)