Which one of the following vitamin diseases can be cured by eating a diet which includes carrot, yellow fruits, vegetables, butter, milk, fish?

The correct option is C - Night blindness.

Night blindness means a person experiences poor vision in the night or low light conditions. It is caused due to the deficiency of vitamin A.

Carrot, yellow fruits, vegetables, butter, fish, milk are the sources of Vitamin A that helps in preventing night blindness.

Thus, the correct answer is (C).