Answer:
The correct answer is their.
Step-by-step explanation:
In this case, we are talking about a possessive adjective.
Possessive adjectives are used to show to whom an object belongs in a sentence, and for each person corresponds a particular possessive adjective, which is always followed by a noun.
In this case the people would be Each of the drama members and the object would be the lines.
Each of the drama members receives the personal pronoun: They
Therefore if I want to establish a possessive adjective, the proper one would be their. Their lines.
Remember the right possessive pronouns for each person:
I --- My + object
He ---- his + object
She ---- her + object
It ----- its + object
We ---- Our + object
You ---- your + object
They ---- their + object.
Given this information, we can say that the correct answer is their.