Final answer:
The rubro-spinal tract originates in the red nucleus of the midbrain and is a motor tract involved in the control of limb movements.
Step-by-step explanation:
The rubro-spinal tract is a descending motor control pathway that originates in the red nucleus, which is a nucleus in the midbrain. It is responsible for mediating control of the limbs on the basis of cerebellar processing. The red nucleus receives output from the cerebellum, and projects motor commands to the spinal cord through the rubro-spinal tract. This involvement with the motor system is crucial, as it helps to compare cerebral motor commands with proprioceptive feedback and send corrective commands to aid movement coordination. The correct answer to the student's question about the origin of the rubro-spinal tract and its type is b. Originates in the red nucleus; motor tract.