A wave represented by the equation $\mathrm{y}=\mathrm{acos}(\mathrm{kx}-\mathrm{\omega t})$ is superposed with another wave to from a stationary wave such that the point x=0 is a node. The equation for the other wave is 

• A

  $\mathrm{asin}(\mathrm{kx}+\mathrm{\omega t})$

• B

  $-\mathrm{acos}(\mathrm{kx}+\mathrm{\omega t})$

• C

  $-\mathrm{acos}(\mathrm{kx}-\mathrm{\omega t})$

• D

  $-\mathrm{\alpha sin}(\mathrm{kx}-\mathrm{\omega t})$