"Which shoes are yours?"
Translation:¿Cuáles zapatos son tuyos?
Both tus and sus are correct. Explanation: There is an informal way to address you = tú (notice the accent), which goes with tu=your, or tus=your when you possess many objects (in this case shoes). The formal way is you=usted (or ustedes for "plural you"), which goes with su=your and sus=your for many objects. This form (su/sus) is also used for his, her, its, their. These rules also apply for most verbs: Tú comes; él/ella/usted come; ustedes/ellos/ellas comen. Hope this helps (and that I'm not wrong).
Yes, and the possessive pronoun for ustedes, ellos and ellas is also sus! (As well as for usted, él and ella)