Which of the following pairs of space and time varying E and B fields would generate a plane electromagnetic wave travel ling in the Z-direction ?

• A

  ${\mathrm{E}}_{\mathrm{x}},{\mathrm{B}}_{\mathrm{y}}$

• B

  ${\mathrm{E}}_{\mathrm{V}},{\mathrm{B}}_{\mathrm{X}}$

• C

  ${\mathrm{E}}_{\mathrm{x}},{\mathrm{B}}_{\mathrm{z}}$

• D

  ${\mathrm{E}}_{\mathrm{z}},{\mathrm{B}}_{\mathrm{x}}$