I was like , " Ahaha ! It 's locked ! " I started having a laughing fit but tried to keep quiet and then when my mum tried to open the door it would n't budge either so we were both standing by the door , in the dark with ABBA playing , pissing ourselves with laughter . Then she tried again and it did budge and we nearly fell out of the room .

Question: Why is the narrator acting so quiet in their room ?
Answer: None of the above choices .They are trying to avoid detection .They are reading a book .They are listening to ABBa in headphones .