A wave travelling in the +ve x-direction having displacement along y-direction as 1m, wavelength $2 \pi m$ and frequency of $\frac{1}{\pi}$ Hz is represented by :

Question

( A ) $y = \sin (10 \pi x – 20 \pi t) $
( B ) $y = \sin (2 \pi x + 2 \pi t)$
( C ) $ y = \sin (x – 2t)$
( D ) $ y = \sin (2 \pi x – 2 \pi t) $