The components of fourth generation dentin bonding systems are described as: (A) Self etching adhesive, (B) Self etching primer/adhesive, (C) Total etch, multi bottle, (D) Total etch, single bottle
Answer is C. As in the fourth-generation adhesives, enamel and dentin are etched simultaneously; these systems were initially called the “total-etch” technique, now they are commonly known as the “three-step etch-and-rinse” technique.
Ref : Talal A, Nasim HM, Khan AS. Enamel etching and dental adhesives. InAdvanced Dental Biomaterials 2019 Jan 1 (pp. 229-253). Woodhead Publishing