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, \({M_R}\; = \frac{W}{{16}} \times 3 \times {R^2} = \frac{{3W{R^2}}}{{16}}\)