$0.27\mathrm{ }\mathrm{g}$ of a long chain fatty acid was dissolved in $100{\mathrm{ }\mathrm{c}\mathrm{m}}^3$ of hexane. $10\mathrm{ }\mathrm{m}\mathrm{L}\mathrm{ }$ of this solution was added dropwise to the surface of water in a round watch glass. Hexane evaporates and a monolayer is formed. The distance from edge to centre of the watch glass is $10\mathrm{ }\mathrm{c}\mathrm{m}$ . What is the height of the monolayer?
[Density of fatty acid $=0.9\mathrm{ }\mathrm{g}\mathrm{ }\mathrm{c}{\mathrm{m}}^{-3};\mathrm{\pi }=3]\mathrm{ }$

• A

  ${10}^{-4}\mathrm{ }\mathrm{m}$
• Correct answer
  B

  ${10}^{-6}\mathrm{ }\mathrm{m}$
• C

  ${10}^{-8}\mathrm{ }\mathrm{m}$
• D

  ${10}^{-2}\mathrm{ }\mathrm{m}$

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