Astronomer: This country's space agency is currently building a new space telescope that is, unfortunately, way over budget. Some people argue that the project should be canceled. But that would be a mistake. If we cancel it now, all the money that has already been spent—which is more than the additional cost required to complete the project—would be wasted.
Which one of the following principles, if valid, would most help to justify the astronomer's argument?
A government agency should not cancel a partially completed project unless the amount of money already spent on the project is small relative to the agency's overall budget.
In other words, if the spending on a project amounts to a significant portion of the agency's overall budget, then it should not be cancelled. While the necessary condition here is correct, the sufficient condition isn't; (A) isn't triggered by the stimulus.
It's subtle, but the details matter here: the sufficient condition for (A) is about the sunk cost proportional to the agency's overall budget, but the stimulus never mentions the space agency's overall budget. The correct answer needs to trigger based on the proportion of the project budget that's already been spent, and that's not the case with (A).
If more than half of the total cost of a project has already been spent, then the project should be completed.
(B) is properly triggered by the stimulus: the money already spent is more than the additional cost required for completion, i.e. more than half. And (A) leads to the correct conclusion that we should complete the project, i.e. not cancel it. This effectively bridges the gap in the astronomer's reasoning, justifying the argument.
If it becomes clear that the total cost of a project will be more than twice the amount originally budgeted, then the project should be canceled.
There are two issues here: (C) doesn't trigger, and it leads to the wrong conclusion. We know that the project is over budget, but we don't know if it will cost more than twice the original budget, so (C) doesn't trigger. And even if it did, it would tell us to cancel the project, when the conclusion we need is not to cancel.
One should not commit additional funding to a project just because one has spent considerable money on it in the past.
This is basically the opposite of the assumption the astronomer relies on, so does not justify the argument. The astronomer's whole argument is that we've spent so much already, we may as well finish the project. (D) says that past spending is not a reason to keep going, which would undermine the astronomer's reasoning.
In determining which scientific projects to fund, governments should give priority to the projects that are most likely to lead to important new discoveries.
We have no idea how likely the telescope—or any other project—is to lead to any new discoveries, so (E) isn't triggered by the stimulus. The correct answer needs to apply based on the amount of money that's already been spent on the telescope, not any other consideration.