Night blindness results from a deficiency of Vitamin-A. Night blindness is a condition in which a person has difficulty seeing in low light or at night. Vitamin-A is essential for maintaining good vision and is important for the functioning of the retina, which is responsible for converting light into electrical signals that can be interpreted by the brain.

Option 1: Glucose is a source of energy for the body and is not directly related to vision.

Option 2: Vitamin-E is an antioxidant that helps protect cells from damage but is not specifically related to night blindness.

Option 3: Vitamin-B2, also known as riboflavin, is important for normal cell growth and function but is not directly linked to night blindness.

Therefore, the correct answer is option 4, Vitamin-A.