Answer: B

Reasoning: A tertiary monoblock contains three bonded interfaces (dentin–sealer, sealer–coating, coating–core). ActiV/Active Gutta-Percha cones are coated with glass-ionomer that bonds to a glass-ionomer sealer, which in turn bonds to dentin, giving the required three-layer (“tertiary”) monoblock. Resilon forms only a secondary monoblock, orthograde MTA a primary monoblock, and conventional gutta-percha with AH Plus is not a monoblock at all [Tay & Pashley 2007, PMID 17368325; Karapinar-Kazandağ 2010, PMID 20417137].