[单选题]
A 2.0-kg mass is hung from a spring of spring constant)0g xbh7 )epwm 18 2:wv0wer+kv v N/m, displaced slightly from its equilibrium position, and released. Wharw2we+0vv :kv t is the frequency of its vibration?
A. $0.48 \; Hz$
B. $0.95 \; Hz$
C. $1.5 \; Hz$
D. none of the above