Answer:
C.) Your
It is your, because if you go through the answers, replace them with the word, and does the sentence 'Don't worry; you will get yours turn.' make sense? No, try the next one then. You're means you are, so read the sentence saying you are replacing the blank. If it doesn't make sense check the next answer.
Also, your is a possessive adjective, and yours is a possessive pronoun.