Answer: A

Reasoning: The buccal (facial) view of the maxillary first and second premolars shows very similar features—a single sharp buccal cusp, a pentagonal-shaped crown and comparable buccal ridge morphology. In contrast, the lingual, occlusal and proximal views reveal obvious distinctions (eg, lingual cusp height, mesial developmental concavity, occlusal outline). Hence the two teeth most closely resemble each other when examined from the buccal aspect [van Reenen & Reid 1996, PMID 9462038; Ahmad & Alenezi 2016, PMID 27106718].