A 1000-N boulder on the right end of a seesaw is raised when the left end of the seesaw is pushed downward. If both ends of the seesaw are equal distances from the fulcrum, then to raise the boulder, the left end should be pushed downward with a minimum force of
a. 500 N
b. 750 N.
c. more than 1000 N.
d. 1000 N.