The correct answer is option 1: kinetic energy is always greater than zero.

When a particle is moving freely, it means that it is not subject to any external forces or constraints. In this scenario, the only form of energy that the particle possesses is kinetic energy. Kinetic energy is the energy of motion and is determined by the mass and velocity of the particle.

Since the particle is in motion, it means it has some velocity, and therefore it possesses kinetic energy. The kinetic energy of a particle is always greater than zero, as long as it is in motion. This is because even if the particle has a very small mass or a very small velocity, the product of mass and velocity will still result in a non-zero value for kinetic energy.

Options 2, 3, and 4 are incorrect because they incorrectly state that the potential energy or kinetic energy is less than zero. Kinetic energy can never be less than zero as it is the energy of motion, and potential energy can never be negative for a freely moving particle.