An electromagnetic wave with frequency cd and wavelength \[\lambda \] travels in the \[+y\] direction. Its magnetic field is along + x-axis. The vector equation for the associated electric field (of amplitude \[{{E}_{0}}\]) is

• A. \[\overset{\to }{\mathop{E}}\,=-{{E}_{0}}\cos \left( \omega t+\frac{2\pi }{\lambda }y \right)\hat{x}\]
• B. \[\overset{\to }{\mathop{E}}\,={{E}_{0}}\cos \left( \omega t-\frac{2\pi }{\lambda }y \right)\hat{x}\]
• C. \[\overset{\to }{\mathop{E}}\,={{E}_{0}}\cos \left( \omega t-\frac{2\pi }{\lambda }y \right)\hat{z}\]
• D. \[\overset{\to }{\mathop{E}}\,=-{{E}_{0}}\cos \left( \omega t+\frac{2\pi }{\lambda }y \right)\hat{z}\]