Situation: The author predicts that a new digital speeding system is underfunded and understaffed; he goes on to conclude that this underfunding will lead to more trouble than the system is worth.
Reasoning: To weaken this argument, we need to find an unsupported assumption made by the author. In this case, he asserts that the system will generate an increased caseload for the department that handles violation and fines, and the administration cannot afford this. But is this so? Two potential weakeners are that 1) the fines and violations will pay for themselves, or 2) the new system will scare more speeders than it will catch, resulting in a deterrent that overall decreases the number of speeders. Remember to stay flexible! Some arguments will have more than one major assumption. Only one can appear among the answer choices, so if you fixate too early on a single flaw, you may miss other equally valid possibilities.
Choices (A) and (B) both address one of the gaps that we've identified. However, both do so in the wrong direction: they support the claim that the number of tickets will increase. Choice (C) superficially addresses that amount of fines, but since we don't know whether processing a fine pays for itself, this answer doesn't give us enough to work with. And choice (D) is simply too vague and too broad to cast any light on the specific system in a specific city.
Choice (E) is the only remaining answer, and it matches our prediction perfectly. If the new system scares speeders enough to get them to slow down, the increase in speeding violations will never happen. It's the correct answer.