Which two sentences are written using correct punctuation?

marsha—who was working at the front desk—forgot her keycard and had to run back up to her dorm room to get it before her roommate left for class.

after cramming for the final exam late last night—even though i knew the material forwards and backwards—i accidentally forgot to set my alarm and almost missed the bus.

sheila was exhausted, but she couldn't hide her joy after completing the marathon with her personal best time and ahead of ronald, who ran out of steam before the finish line.

it was the middle, of the night and the crickets would not stop their continuous chirping when i had to concentrate fully on beating this game before samantha.

it was all priya could do to stop, laughing when she saw that she had aced her final when she had struggled with chemistry all semester long.