Answer: Option 3: THE SAME
Step-by-step explanation:
The gravitational potential at a point or location is equal to the work per unit mass of a certain body that would be needed to move the body to that point from a reference point or location. The gravitational potential of both the first student that used the elevator and the second student that used the stairs are THE SAME because they both moved from referenced location (first floor) to the other location(second floor) and work is done per unit mass.