Match the disease name to its vitamin using collagen synthesis as the clue.
Vitamin A deficiency causes night blindness, Vitamin B deficiencies cause disorders such as beriberi and pellagra, and Vitamin D deficiency causes rickets in children and osteomalacia in adults. None of these match scurvy.
Scurvy specifically involves weak connective tissue and bleeding gums because collagen cannot be formed properly, and collagen synthesis needs Vitamin C as a cofactor.
\[\boxed{\text{Vitamin C}}\]