Which clinical sign is most specifically associated with severe vitamin A deficiency affecting vision?

• A. Uncontrolled hypercalcemia and nephrocalcinosis from overactive bone resorption and abnormal vitamin D signaling.
• B. Night blindness (difficulty seeing in low light) progressing to xerophthalmia and corneal ulceration.
• C. Spontaneous bruising and mucosal bleeding due to impaired prothrombin activation.
• D. Peripheral neuropathy and paresthesia of the lower limbs due to demyelination of sensory neurons.

Answer: (B)