Electromagnetic Waves: JEE Main 2020 Physics question

A plane electromagnetic wave, has frequency of 2.0 $\times$ 10¹⁰ Hz and its energy density is 1.02 $\times$ 10^–8 J/m³ in vacuum. The amplitude of the magnetic field of the wave is close to ( ${1 \over {4\pi {\varepsilon _0}}} = 9 \times {10^9}{{N{m^2}} \over {{C^2}}}$ and speed of light = 3 $\times$ 10⁸ ms^–1)