The displacement of a wave is expressed as y(x,t)=0.1sin(2πx+100πt), with x in metres and t in seconds. Which option correctly states the direction of propagation of the wave along the x-axis and its frequency?
a) Positive x-direction,50Hz
b) Negative x-direction,100Hz
c) Negative x-direction,50Hz
d) Positive x-direction,100Hz