Final answer:
The appropriate possessive adjective in the sentence is 'leur'.
Step-by-step explanation:
In the sentence 'C'est la penderie de mes parents; c'est', the possessive adjective that should be chosen is leur. This is because the noun 'penderie' is plural, referring to the parents, so we use the plural possessive adjective 'leur'. 'Leur' is used to indicate possession by a third-person plural noun, which matches the situation described in the sentence.
Learn more about Possessive adjectives in French