Which one of the following pairs is not correctly matched ?

Vitamin $B_1$ (thiamine) deficiency causes beri-beri; correctly matched.
Vitamin $B_{12}$ (cyanocobalamin) deficiency causes pernicious anaemia; correctly matched.
Vitamin $B_6$ (pyridoxine) deficiency causes dermatitis, anaemia, convulsions and loss of appetite (anorexia) with nausea; this pairing is acceptable.
Vitamin $B_2$ (riboflavin) deficiency causes cheilosis (cracks at the corners of the mouth), glossitis and dermatitis. Pellagra (the 3 Ds: dermatitis, diarrhoea and dementia) is caused by deficiency of niacin (vitamin $B_3$ or nicotinic acid), not riboflavin.
So the pair that is not correctly matched is Vitamin $B_2$ – Pellagra.
Note: the answer key of the source gives Vitamin $B_6$ – loss of appetite; it is changed here because pellagra is definitely a niacin deficiency disease, not a riboflavin deficiency disease.