Answer: D

Reasoning: Permanent teeth are built from separate centers of calcification called developmental lobes. In the permanent dentition every tooth has a minimum of four such lobes (e.g., incisors and canines arise from three labial lobes plus one lingual-cingular lobe; premolars and many molars add additional lobes but never fewer than four). Therefore the least number of lobes required to form any permanent tooth is four [Ng, 2024, PMID 39060588].