A resonating tube of length $l$, open at one end, is partially filled with water. When placed in gaseous medium-X, a water column of height $l / 5$ generates the third harmonic using a tuning fork with frequency $\nu$. When placed in gaseous medium-Y, a water column of height $l / 3$ generates the fifth harmonic using the same tuning fork. The ratio $v_{\mathrm{X}}: v_{\mathrm{Y}}$ of the velocity of sound in medium- X to medium- Y is

• Correct answer
  A

  $2: 1$
• B

  $4: 1$
• C

  $1: 4$
• D

  $1: 2$

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