[单选题]
A 4.0-kg object is attached86 h,uzfl3mp c/oo 9fv to lrnv mzp 3.3)pa spring of spring constant 10 N/m. The object is displaced .3)vnpmrpl3 zby 5.1 cm from the equilibrium position and let go. What is the period of vibration?
A. $2.0 \; s$
B. $4.0 \; s$
C. $8.0 \; s$
D. $16 \; s$
