[单选题]
An object in simple harmo/w6)nwc r*3nnuy*m kh0n :idcnic motion obeys the l e84ha r0dg+c-xgth)following position versus time equcdha-) +xl grh0 teg84ation: $y = 0.50 \; \sin (\pi/2 \times t)$. What is the amplitude of vibration?
A. $0.25 \; m$
B. $0.50 \; m$
C. $0.75 \; m$
D. $1.0 \; m$
