Which one of the sols acts as a protective colloid?

The disease kala azar is caused by

Which is the correct statement in the case of milk?

During electrosmosis of $Fe(OH)_3$ sol,

Identify the correct statements from the following:
$I$) Sulphur sol is an example of a multimolecular colloid.
$II$) Starch sol is an example of an associated colloid.
$III$) Artificial rubber is an example of a macromolecular colloid.

$10 \ mL$ of $0.5 \ M$ $NaCl$ is required to coagulate $1 \ L$ of $Sb_2S_3$ sol in $2$ hours. The flocculating value of $NaCl$ (in millimoles) is: