In which situation can a duplicate be unfairly admitted in lieu of the original?

The option describing the situation where the authenticity of the original could be questioned provides a good basis for fair admission of a duplicate. In legal evidence, the best evidence rule generally requires that the original document be provided to prove its content. However, when there is uncertainty about the original's authenticity, a duplicate can be considered to fulfill the evidentiary requirements as it serves the purpose of demonstrating the document's contents without needing to rely on a potentially dubious original. Courts often allow duplicates in such contexts to avoid confusion and to streamline the admission of evidence, particularly when the original's integrity is in question.

This aligns with the principle of ensuring that relevant evidence is not excluded simply based on an original document's doubtful status, thereby upholding the goals of justice and factual ascertainment in legal proceedings.