Imran is asking if Mita has packed 'her suitcase', which was previously mentioned. A possessive pronoun is required here to refer to 'your suitcase' without repeating the noun. 'Yours' is the correct possessive pronoun.
Class 6 › English Grammar and Composition › Chapter 4: Possessives › Topic: Activity 1: Filling gaps with possessive adjectives
Aligned to the NCTB national curriculum.