A plane electromagnetic wave is propagating along the direction $\frac{\widehat{i}+\widehat{j}}{\sqrt{2}},$ with its polarization along the direction $\widehat{k.}$ The correct form of the magnetic field of the wave would be (here $B_0$ is an appropriate constant):

• Correct answer
  A

  $B_0\frac{\widehat{i}-\widehat{j}}{\sqrt{2}}\mathrm{c}\mathrm{o}\mathrm{s}\left(\omega t-k\frac{\widehat{i}+\widehat{j}}{\sqrt{2}}\right)$
• B

  $B_0\frac{\widehat{j}-\widehat{i}}{\sqrt{2}}\mathrm{c}\mathrm{o}\mathrm{s}\left(\omega t+k\frac{\widehat{i}+\widehat{j}}{\sqrt{2}}\right)$
• C

  $B_0\widehat{k}\mathrm{c}\mathrm{o}\mathrm{s}\left(\omega t-k\frac{\widehat{i}+\widehat{j}}{\sqrt{2}}\right)$
• D

  $B_0\frac{\widehat{i}+\widehat{j}}{\sqrt{2}}\mathrm{c}\mathrm{o}\mathrm{s}\left(\omega t-k\frac{\widehat{i}+\widehat{j}}{\sqrt{2}}\right)$

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