Final answer:
The nurse should discuss Vitamin A with the client as it is associated with maintaining good vision and preventing night blindness.
Step-by-step explanation:
A nurse who is teaching about dietary intake of micronutrients to a client who has difficulty seeing at night should include Vitamin A in the discussion. Vitamin A is known for maintaining good vision, particularly in low light conditions, and a deficiency in this vitamin can lead to night blindness. In contrast, Vitamin C is a water-soluble vitamin essential for many functions in the body but not directly associated with improving night vision. Vitamin D is important for bone health and the nervous system, and Vitamin K is crucial for blood clotting. Therefore, Vitamin A should be emphasized for a client who has difficulty seeing at night.