The correct option is C Vitamins
Enzymes are simple if they are made up of only proteins example pepsin, amylase etc. while conjugate enzymes have an additional non protein organic coenzyme or inorganic cofactor. Loosely attached organic cofactors are called as coenzymes example NAD, FAD TPP etc. Coenzymes are generally derived from vitamins like Thiamine (TPP), Riboflavin (FMN, FAD), Niacin (NAD), Pantothenate (CoA).