A parallel beam of wavelength $\lambda =450\times {10}^{-9}\mathrm{m}$ passes through a long slit of width $2\times {10}^{-4}\mathrm{m}$. The angular divergence for which most of light is diffracted is

• A

  $5.4\times {10}^{-4}\mathrm{rad}$

• B

  $4.5\times {10}^{-3}\mathrm{rad}$

• C

  $3.5\times {10}^{-3}\mathrm{rad}$

• D

  $2.8\times {10}^{-4}\mathrm{rad}$