Among the following, the equation representing a progressive wave is (A) $y=2 \cos 3 x \sin 10 t$ (B) $\mathrm{y}=2 \sqrt{\mathrm{x}-\mathrm{vt}}$ (C) $y=3 \sin (5 x-0.5 t)+4 \cos (5 x-0.5 t)$ (D) $y=\cos x \sin t+\cos 2 x \cdot \sin 2 t$

• A

  $A$ and $D$
• Correct answer
  B

  $\mathrm{C}$
• C

  $\mathrm{A}, \mathrm{C}, \mathrm{D}$
• D

  B

Hence, the correct answer is option: 'B'.