Answer:
A. Proprioception.
Step-by-step explanation:
Proprioception is a phenomena whereby awarness of the position,form and locomotion of the body is observed. Mechanosensory neurons, proprio-receptors cells that are located in the muscles are responsible for the moderation and regulation of proprioception.
As given in the question, during physical examination, when the veterinarian curls the dogs foot under so it's upside down. The ability for the dog to immediately switch the foot back to the normal standing position is as a aftermath effect of the sense of Proprioception.