Option C — Polythene bag, rubber band, ball pen.
All three are human-made materials not broken down by biological processes, making the entire group non-biodegradable.
Source: Our Environment, Chapter 13, Section 13.2.2
The question asks for the group where none of the items is biodegradable. Polythene, rubber bands, and ball pens are all synthetic/non-biodegradable materials. Options A, B, and D each contain at least one biodegradable item (vegetable peels, cow dung, paper, fruits, bones, leather — all break down biologically). Examiners expect students to recall that plastics and synthetic materials resist enzyme/bacterial breakdown.