Kinetic theory is a theory that explains the behavior of matter and its changes in state. This theory tells us or assumes the following:
The matter is composed of very small particles in continuous motion, between them there is empty space.
Molecules perform elastic collisions. In a collision, the kinetic energy of a particle is transferred to another particle without loss of global energy.
The kinetic energy of particles increases with increasing temperature, the kinetic energy is related to the velocity of the particles. And in the same way, if the temperature decreases, the kinetic energy will also decrease and the molecules will move slower.
So, the correct statement regarding the Kinetic Molecular Theory will be: As temperature decreases, this causes velocity to decrease