Explanation :
It is given that,
Speed of the wave, [tex]v=3\times 10^8\ m/s[/tex]
Wavelength of the wave, [tex]\lambda=0.6\ m[/tex]
We know that,
[tex]v=f \lambda[/tex]
where
v is the speed of the wave
[tex]\lambda[/tex] is the wavelength of the wave
f is the frequency of the wave
[tex]f=\dfrac{v}{\lambda}[/tex]
[tex]f=\dfrac{3\times 10^8\ m/s}{0.6\ m}[/tex]
[tex]f=500000000\ Hz[/tex]
or
[tex]f=5.0\times 10^8\ Hz[/tex]
So, the correct option is (d).