[单选题]
A 0.200-kg mass attached to the end of a spring cause rmz5(a mw7c7qs it to stretch 5.0 cm. If.0tex lxu:-kg f wxj:* another 0.200-kg mass is added to the spring, the px-0fe k:g*t wu: l.jxxotential energy of the spring will be
A. the same.
B. twice as much.
C. 3 times as much.
D. 4 times as much.
