An air column in a tube of length 50 cm, closed at one end is vibrating in its fifth harmonic. The phase difference between a particle at the open end and a particle at 42 cm from the open end is

• A

  $90^{\circ}$
• B

  $180^{\circ}$
• Correct answer
  C

  $0^{\circ}$
• D

  $270^{\circ}$

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