A resonance tube is old and has a jagged end. It is still used in the laboratory to determine the velocity of sound in air. A tuning fork of frequency $512\mathrm{ }\mathrm{Hz}$ produces first resonance when the tube is filled with water to a mark $11\mathrm{ }\mathrm{cm}$ below a reference mark, near the open end of the tube. The experiment is repeated with another fork of frequency $256\mathrm{ }\mathrm{Hz}$ which produces first resonance when water reaches a mark $27\mathrm{ }\mathrm{cm}$ below the reference mark. The velocity of sound in air, obtained in the experiment, is close to

• A

  $335 \mathrm{m} {\mathrm{s}}^{-1}$
• B

  $341 \mathrm{m} {\mathrm{s}}^{-1}$
• C

  $322 \mathrm{m} {\mathrm{s}}^{-1}$
• Correct answer
  D

  $328 \mathrm{m} {\mathrm{s}}^{-1}$

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