An argument claims that because a town implemented a new recycling program, and then saw a decrease in overall waste sent to landfills, the recycling program *must be* the sole cause of the waste reduction. This reasoning most clearly exemplifies which common logical flaw?

The correct answer to the question "An argument claims that because a town implemented a new recycling program, and then saw a decrease in overall waste sent to landfills, the recycling program *must be* the sole cause of the waste reduction. This reasoning most clearly exemplifies which common logical flaw?" is Option C: Post hoc ergo propter hoc (faulty causation).

The other options — A) Ad hominem, B) False dilemma, D) Appeal to authority — are incorrect for this GMAT Exam Prep question. As explained above: "Post hoc ergo propter hoc" is the fallacy of assuming that because one event followed another, the first event must have caused the second, overlooking other potential factors.