The oscillations represented by curve 1 in the graph are expressed by equation`x=Asinomegat.` The equation for the oscillation represented by curve `2` is expressed as
A. `x=2A sin (omegat-pi//2)`
B. `x=2Asin(omegat+pi//2)`
C. `x=-2Asin(omegat-pi//2)`
D. `x=A sin (omegat-pi//2)`