Final answer:
Detail grinders primarily use discs as attachments to smooth and polish intricate metallic works. The answer is d) Discs. While brushes are also used in certain cases, discs are specifically designed for polishing and grinding.
Step-by-step explanation:
A detail grinder smooths and polishes intricate metallic work using attachments that are typically referred to as discs. The correct answer to the question is d) Discs. These discs come in various forms, such as grinding discs for material removal and polishing discs for finishing surfaces.
Some detail grinders may also use brushes for certain applications to clean surfaces or reach into intricate areas, but when talking about smoothing and polishing, discs are the primary attachments.