[单选题]
An object in simple harmonic motion obeys the f:f 9df vcaon39o xkp.2vl-f)r xmgkqzq35r 8+4m 0kze ollowing position versus time equatio+k8k0zl-) reqf4gv r x q5mzm3n: $y = 0.50 \; \sin (\pi/2 \times t)$. What is the period of vibration?
A. $1.0 \; s$
B. $2.0 \; s$
C. $3.0 \; s$
D. $4.0 \; s$
