What is the wavelength range of visible light?

• A
  $4 \times 10^{-7} \; m$ to $8 \times 10^{-7} \; m$
• B
  $4 \times 10^{-9} \; m$ to $8 \times 10^{-9} \; m$
• C
  $4 \times 10^{-5} \; m$ to $8 \times 10^{-5} \; m$
• D
  $4 \times 10^{-6} \; m$ to $8 \times 10^{-6} \; m$