What is the object's velocity when its potential energy is 2/3E?

An object of mass m attached to a spring of force constant k oscillates with simple harmonic motion. The maximum displacement from equilibrium is A and the total mechanical energy of the system is E.

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What is the object's velocity when its potential energy is 2/3E?

A: /- sqrt(k/m)*A

B: /- sqrt(k/m)*sqrt(2/3)*A

C: /- (sqrt(k/m))*(A/sqrt(3))

D: /- (sqrt(k/m))* (A/sqrt(6))