Final answer:
The recoil speed of the 300-kg cannon will be lesser than the speed of the 25-kg cannonball, due to the conservation of momentum and the difference in their masses.
Step-by-step explanation:
When a 300-kg cannon fires a 25-kg cannonball, the recoil speed of the cannon will be lesser than the speed of the cannonball if momentum is conserved. The momentum before and after the event must be equal, assuming there are no external forces acting on the cannon-cannonball system. Since momentum is the product of mass and velocity, and the cannon has a greater mass than the cannonball, it must have a proportionately lower velocity to maintain the momentum balance. Therefore, the correct answer is (c) Lesser.