Which hypothetical scenario would result n the moon not having different phases?

If the moon were to orbit Earth in a perfectly circular path and always maintained the same side facing Earth—similar to how it currently does due to tidal locking—then it would not exhibit different phases. In this scenario, the moon would appear as a constant full moon from Earth, as we would only see one hemisphere. Additionally, if the sun's position relative to Earth and the moon remained unchanged, there would be no variation in illumination, resulting in a lack of phases.