An Object Is Attached to a Vertical Spring and Bobs

Multiple Choice

An object is attached to a vertical spring and bobs up and down between points A and B.Where is the object located when the elastic potential energy of the system object-spring is a minimum?

A) at either A or B
B) midway between A and B
C) one-third of the way between A and B
D) one-fourth of the way between A and B
E) at none of the above points