What Is the Frequency of Light Emitted by a Helium-Neon

What is the frequency of light emitted by a helium-neon laser if the wavelength of the light is 632.8 nm and the speed of light is 3 × 10 ⁸ m/s?

A) 4.74 × 10¹⁴ s ^{− 1}
B) 4.74 × 10⁵ s ^{− 1}
C) 1.58 × 10 ^{− 3} s ^{− 1}
D) 2.11 × 10 ^{− 15} s ^{− 1}
E) 1.58 × 10 ^{− 15} s ^{− 1}