Final answer:
Sugar's inability to move his left eye to the left indicates a problem with the abducens nerve (cranial nerve VI), which controls the lateral rectus muscle responsible for lateral eye movement.
Step-by-step explanation:
If Candy's dog Sugar is unable to move his left eye to the left, the problem likely involves the nerve responsible for lateral movements of the eye. The cranial nerve in question is the abducens nerve, also known as cranial nerve VI. This nerve specifically innervates the lateral rectus muscle, which is the muscle responsible for pulling the eye outward, allowing for movement to the side. If Sugar's left eye won't track to the left, it suggests a possible issue with the left abducens nerve. In contrast, issues with the ophthalmic connections, such as the oculomotor nerve (cranial nerve III) or the optic nerve (cranial nerve II), would affect pupillary reflexes or visual processing, respectively, rather than lateral eye movement.