Each option below describes a parameterization of a curve in the plane, where s≥0 denotes the parameter. Which parameterization traces the unit circle once counter-clockwise starting at (1,0) and moves with constant speed 1?
a) x=cos2s,y=sin2s
b) x=coss,y=sins
c) x=coss,y=−sins
d) x=coss,y=sins+1