[单选题]
An object undergoes simple harmonic motion. The graph shows ;o49kb -u/h18yf2jr qmk ljkt how acceleratvb:9q2kl qc2h ion $a$ varies with displacement $x$ from the equilibrium position of the object.
Which of the following gives the displacement of the object when its kinetic and potential energies are equal?
A. $\sqrt{2}\,m$
B. 1 m
C. $\frac{\sqrt{2}}{2}$
D. $\frac{1}{2}$
