Hi, we can do a comparisson. Recall that potential energy is defined as m*g*h where m is the mass in kg, g is gravitational acceleration (9.8m/s^2) and h is the height therefore:
A:B:C:D=30×g×1.5:20×g×2:30×g×2:20×g×1.5 since all of them have the term of g, we can "kill" the term hence we have that:
A:B:C:D=45:40:60:30 hence we know the option c has the most potential energy
