Adelia:Sinta,l want to return your book that i Borrowed yesterday.Many thanks.

Sinta:You're wellcome
Adelia:I am sorry.I brought itu yesterday
Sinta:It's ok.perhaps,you still need itu to you.Please forgive me.
Adelia:No.I forgot to return It to you. please forgive me.
Sinta:Never Mind.

I forgot to return it_ to you. The underlined word refres to……
A.Sinta's book
B.Their book
C.Adelia's book
D.Sinta's friend​

Adelia:Sinta,l want to return your book that i Borrowed yesterday.Many thanks.