A.) Their
Their sister is happy to babysit, so you mustn't worry about it.
Their is the 3rd person plural adjective. It is used to describe something or someone that belongs to them.
They're is a contraction of "they are" and it is most often followed by a present participle or a verb that ends with -ing.
The answer is to this question is true
Exposition
is your answer :D
Answer:
It means an excessive ammount of something
Explanation:
(at least thats what it says in the dictionary lol)