This puzzle asks you to find the single category linking five clues: Prescriptions, Mechanical pencils, Fuel tanks, Empty water bottles, and Printers (with toner + paper). The answer is Things that are refilled. Each clue is a concrete example of a broader collection. The answer is the set label that every row belongs to without stretching the meaning. With only "Prescriptions", many categories could fit. Hold your first guess and watch what clue 2 eliminates. "Prescriptions" and "Mechanical pencils" must share one repeatable link — not a coincidence between two words. By clue 3 ("Fuel tanks"), "Things that are refilled" should explain all three without bending meanings. "Empty water bottles" strengthens "Things that are refilled" rather than opening a new theory. The final clue ("Printers (with toner + paper)") confirms "Things that are refilled" — if it still fits naturally, the category is locked. Use the Solution tab above for an interactive clue-by-clue walkthrough, or the Solved board tab for the complete answer at a glance.