The stimulus gives us a premise about the "end" of an action: it is defined as an action's intended outcome, and the value of that intended outcome is the only reason for an action. We are then given some concessions — that not every end's value will justify every means, and perhaps that no end can justify every means — before we get the argument's conclusion: nothing will justify a means except an end's value.

Language clues can get us to the main conclusion pretty quickly. We know the first sentence is a premise because it is used as support by the next sentence, which starts with "so." We know that both clauses set off by the phrase "while it is true" are concessions, and so we're left with a conclusion clearly marked by the "So... it is clear that..." set-up: nothing will justify a means except an end's value.

If you've gotten this far, you might have looked over the answer choices and noticed that the hard part might be recognizing the "translation" of that conclusion. Remember that it's a statement about a necessary condition: if a means is justified, it must be justified by the end's value.

justified → end's value

As the concessions in the argument state, this doesn't mean that an end's value is always sufficient to justify the means to that end. But whenever a means is justified, it must be by the value of the end — i.e., the intended outcome of that action.