Super! (pronounced "Syupah!")
The correct answer is:
a.) a bedroom for several students.
The building where students sleep, study and often eat is called the House; dormitories are large sleeping rooms for 4-8 younger students who have a separate place to study. Older students have single or double rooms with beds and desks for studying. "Dormitory" in Britain is pronounced "dormitry."
Congratulations! Now you can speak British English!