A box of mass 53g is attached to a horizontal spring with a spring constant of 103 N/m. The spring is then extended by 9 cm, and the box is subsequently released. Calculate the speed of the box at the moment when the entire elastic potential energy is converted to the box's kinetic energy.

A) 1.54 m/s
B) 1.92 m/s
C) 2.12 m/s
D) 2.31 m/s