Two ice skaters initially stand at rest on frictionless ice. Skater A has a mass of 60kg, and Skater B has a mass of 40kg. They push off each other and move in opposite directions. Which statement describes the motion of the center of mass of the two-skater system after they separate, assuming no external horizontal forces act?
a) It moves in the direction of Skater A because A has the greater mass.
b) It remains halfway between the skaters as they glide apart.
c) It remains at rest at the point where the skaters pushed off.
d) It moves in the direction of Skater B because B attains the greater speed.