A string vibrates according to the equation $\mathrm{y}=5\sin \left(\frac{2\mathrm{\pi x}}{3}\right)\cos 20\mathrm{\pi t}$, where x and y are in cm and t in sec. The distance between two adjacent nodes is 

• A

  3 cm

• B

  4.5 cm

• C

  6 cm

• D

  1.5 cm