"Tuvix" or "The One Where Janeway Tries Her Hand At Ethics"
(to be fair, the situation was explicitly scripted to have no 'and every lived happily ever after' solution. Janeway made the hard call, and I think the correct one.).
Next: Resolutions
(to be fair, the situation was explicitly scripted to have no 'and every lived happily ever after' solution. Janeway made the hard call, and I think the correct one.).
Next: Resolutions