A colloidal system has what size of particles?
(a) $10^{-4} \mathrm{~m}$ to $10^{-10} \mathrm{~m}$
(b) $10^{-5} \mathrm{~m}$ to $10^{-7} \mathrm{~m}$
(c) $10^{-9} \mathrm{~m}$ to $10^{-12} \mathrm{~m}$
(d) $10^{-6} \mathrm{~m}$ to $10^{-9} \mathrm{~m}$