7. A 2.00-kg object is attached to a spring and placed on a horizontal, smooth surface. A horizontal force of 20.0 N is required to hold the object at rest when it is pulled 0.200 m from its equilibrium position (the origin of the x axis). The object is now released from rest with an initial position of xᵢ = 0.200 m, and it subsequently undergoes simple harmonic oscillations. The total energy of the oscillating system is
(A) 0.50 J.
(B) 1.25 J.
(C) 1.50 J.
(D) 1.75 J.
(E) 2.00 J.