What Force Is Exerted by Exactly One Atmosphere of Pressure $\pi$

What force is exerted by exactly one atmosphere of pressure (1.013 *10⁵ Pa) on a mercury barometer with an inner diameter of 20.00 mm?
Recall that the area of a circle is A = $\pi$ r² and that 1 N = 1 kg m/s².

A) 31.82 N
B) 15.91 N
C) 127.3 N
D) 3.182 * 10⁷ N
E) 40.52 N