What is the particle size range in a colloidal system?

• A
  $10^{-4} \ m$ to $10^{-10} \ m$
• B
  $10^{-5} \ m$ to $10^{-7} \ m$
• C
  $10^{-9} \ m$ to $10^{-12} \ m$
• D
  $10^{-9} \ m$ to $10^{-6} \ m$