(C) DDT, Polyester, Glass
DDT is a pesticide, polyester is a synthetic fibre, and glass is an inert material — all three are non-biodegradable as they are not broken down by biological processes.
The key is knowing which materials resist breakdown by bacteria/saprophytes. DDT, polyester, and glass are all human-made/inert substances that persist in the environment. In option (A), leather is biodegradable. In (B), cotton and wood are biodegradable. In (D), silk and wool are biodegradable (animal proteins). Only option (C) has all three as non-biodegradable.