What anomaly results in a bifid crown with a single root and pulp chamber?

The configuration described, where there is a bifid (split) crown but a single root and pulp chamber, is indicative of gemination. In gemination, a single tooth bud divides partially during development, leading to the formation of two crowns that are joined at the crown but share a single root and a single pulp chamber. This phenomenon typically results in the appearance of two crowns that may closely resemble each other, often being more pronounced in primary teeth.

In contrast, fusion involves the complete joining of two separate tooth buds, resulting in a single tooth with two roots or root canals, making the structures less distinct compared to gemination. Twinning or twinning anomalies refer to the creation of two distinct crowns from a single tooth bud but would typically have separate pulp chambers. Concrescence describes the fusion of the roots of two adjacent teeth after they have developed, which does not pertain to the crown structure at all.

Therefore, gemination accurately reflects the anomaly where there is a bifid crown associated with a single root and pulp chamber, making it the correct choice for this question.