[单选题]
An object in simple harm:rlp n kaw 1dsa4dcd 0a:o3n:3onic motion obeys the following position versus til(x* a :f ut5c0h/vic -flr;ywme equation5lw:f/*vl ary;-i(chxc f0u t : $y = 0.50 \; \sin (\pi/2 \times t)$. What is the amplitude of vibration?
A. $0.25 \; m$
B. $0.50 \; m$
C. $0.75 \; m$
D. $1.0 \; m$
