A transverse wave of amplitude `0.5 m` and wavelength 1 m and frequency 2 Hz is propagating in a string in the negative x - direction. The expression for this wave is [
A. `y(x,t) = 0.5 sin (2pix - 4pit)`
B. `y(x,t) = 0.5 cos (2pix - 4pit)`
C. `y(x,t) = 0.5 sin (pix - 2pit)`
D. `y(x,t) = 0.5 cos (2pix - 2pit)`
