**Core Concept**
The hopping and placing reflex is a complex motor response that involves the coordination of multiple sensory inputs from the visual, vestibular, and proprioceptive systems to facilitate locomotion and balance. This reflex is essential for the maintenance of posture and the execution of voluntary movements.

**Why the Correct Answer is Right**
The hopping and placing reflex relies heavily on the integration of sensory information from the cerebellum, which is responsible for processing and coordinating motor activities. Decortication, or the removal of the cerebral cortex, disrupts this complex process, leading to a loss of the hopping and placing reflex. This is because the cerebellum receives input from the cerebral cortex, which is essential for the refinement and modulation of motor responses. Without this cortical input, the cerebellum is unable to coordinate the complex motor activities required for the hopping and placing reflex.

**Why Each Wrong Option is Incorrect**
**Option B:** The tonic neck reflex, also known as the righting reflex, is mediated by the vestibular system and is not directly dependent on cortical input. It is preserved in decorticate animals.
**Option C:** The tonic labyrinthine reflex is also a vestibular-mediated response and is not affected by decortication. It helps to maintain posture and balance.
**Option D:** The stretch reflex is a monosynaptic reflex arc that is mediated by the spinal cord and is not dependent on cortical input. It is preserved in decorticate animals.

**Clinical Pearl / High-Yield Fact**
The hopping and placing reflex is a good indicator of the integrity of the cerebral cortex and its connections with the cerebellum. Its loss in a patient with a head injury or stroke suggests significant cortical damage.

**✓ Correct Answer: A. Hopping and placing reflex**