Given the following context:

Burma is a confused girl who likes to party. One day she meets some strangers in a bar who invite her and her group to a party. She goes to the party with her friends, they all drink alcohol, only the girls at the party smoke marijuana unknowingly, and keep on laughing. Burma and her boyfriend have sex on the beach while her friends go skinny-dipping.
One of the girls drowns at the skinny-dipping party and the rest of the friends must keep the details of the party a secret. When Burma tells her boyfriend she is pregnant (from their beach encounter), she pressures him to marry her. He says everything will be fine and turns to the strangers who threw the party for a job to support his family-to-be. The stranger gives him a job unloading smuggled drugs from a secret shipment to the docks. The police find out about this shipment, chase the smugglers, and shoot and kill Burma's boyfriend.
After Burma finds out about this news, she runs away from home, is forced to give her child up for adoption, and becomes a drug dealer. Burma moves on to harder drugs injecting heroin into herself. In the film's ending, Burma hatches a plan to kidnap and ransom her sister's adopted daughter for $50,000, but she later finds out that the child is, in fact, her own.

answer the following question:

Whose sister adopts Burma's baby? 

Burma