Calculate the number of sols which are negatively charged

${\mathrm{Fe}}_3{\mathrm{O}}_3\cdot x{\mathrm{H}}_2\mathrm{Osol}$	${\mathrm{Sb}}_2{\mathrm{S}}_3\text{ sol }$
$\mathrm{Ag} \mathrm{sol}$	$\mathrm{Cu} \mathrm{sol}$
blood	basic dye
sol of clay	sol of starch
sol of sodium stearate	sol of sodium laurysulphate
sol of charcoal

the number of sols which are negatively charged is 8.

Negatively charged sols include those made of sol of starch, sol of sodium lauryl sulfate, $\mathrm{Cu} \mathrm{sol},$ ${\mathrm{Sb}}_2{\mathrm{S}}_3\text{ sol }$, $\mathrm{Ag} \mathrm{sol}$, blood, sol of clay, sol of charcoal