A uniformly charged disc of radius R having surface charge density `sigma` is placed in the xy plane with its center at the origin. Find the electric field intensity along the z-axis at a distance Z from origin :

Options

A. `E=(sigma)/(2epsilon_(0))((1)/((Z^(2)+R^(2)))+(1)/(Z^(2)))`
B. `E=(sigma)/(2epsilon_(0))(1+(Z)/((Z^(2)+R^(2))^(1//2))+(1)/(Z^(2)))`
C. `E=(2epsilon_(0))/(sigma)((1)/((Z^(2)+R^(2))^(1//2))+Z)`
D. `E=(sigma)/(2epsilon_(0))(1-(Z)/((Z^(2)+R^(2))^(1//2)))`