vec$(B)$

At time $t_0,$ a localized magnetic field is detected at $($:$-4\mathrm{.}84,-4\mathrm{.}74,0$:$)m,$ with a direction hat$(B)=($:$0\mathrm{.}7306,-0\mathrm{.}6828,0$:$).$ A short time later, this localized magnetic field is detected at $($:$4\mathrm{.}59,5\mathrm{.}35,0$:$)m.$ It is determined that this magnetic field is due to passing electromagnetic radiation.

A$.$ What is hat$(k),$ the direction of propagation of the radiation?

B$.$ What is hat$(E),$ the direction of the electric field at time $t_0?$