A dam is having a curved surface as shown in the figure. The height of the water retained by the dam is 20 m density of water is 1000 kg/m3. Assuming g as 9.81 m/s2, the horizontal force acting on the dam per unit length is
a. 1.962x 102N
b. 2x105N
c. 1.962x106N
d. 3.924x106N