Concept:Polyamides are polymers joined by amide linkages (−CO−NH−).Explanation:Among the given options, Nylon 6,6 contains amide linkages in its backbone.These linkages form by the reaction between carboxylic acid groups and amine groups.SBR is a rubber, Bakelite is a phenol-formaldehyde polymer, and melamine formaldehyde is a cross-linked polymer.Hence, Nylon 6,6 is the correct polyamide.Answer:D. Nylon 6,6