Final answer:
The d. corticospinal tract carries signals for precise, finely coordinated limb movements.
Step-by-step explanation:
The correct option that carries signals for precise, finely coordinated limb movements is d. corticospinal tract. The corticospinal tract is responsible for generating voluntary movements and is involved in the control of intricate movement patterns, such as those required for hand dexterity and fine motor skills.
It originates from the motor cortex in the brain and travels down through the spinal cord to synapse with the lower motor neurons in the ventral horn, which then activate the muscles responsible for limb movements.