[单选题]
A mass undergoes SHM with amplitude of 4 cm. The energy ib *n)8.x7s/de8pagx7tpwc eis 8.0 J avmf-3o4( szu it this time. The mass is cs m v(3fziu-o4ut in half, and the system is again set in motion with amplitude 4.0 cm. What is the energy of the system now?
A. $2.0 \; J$
B. $4.0 \; J$
C. $8.0 \; J$
D. $16 \; J$
