a b c d

b

Let resistivity = $\rho$ , Length of R = L thickness = t Resistance of R is $R_1 = \frac{\rho L}{L.t} = \frac{\rho}{t}$ Resistance of S is $R_2 = \frac{\rho 2L}{2L.t}=  \frac{\rho L}{L.t} = \frac{\rho}{t} $ Resistance of R is same as Resistance of S.