Which word correctly completes the sentence? My brother and sister likes ... new coats?

a. Their

b. They're

c. There

The answer would be their

some examples so you know which there should be used are

let's go over there

that's their car

and they're in town

The answer is A.

A is a possesive pronoun

B is an abbreviation of they are

C is the word that showing where is the place.

Actually these three words sounds the same but their mean and spelling are different.

The sentence is My brother and sister likes their new coats