One reason that colonists did not enslave the native population
they had big hearts and didn’t want to upset them.
they feared them more.
they were more susceptible to european disease.
they didn’t know anything about the terrain and would be useless to them.

3 or C

Explanation:

Well for one, most of the Native's were in fact enslaved by the colonist's for several different reasons, automatically getting rid of answers 1 and 4, leaving 2 and 3 to choose from, at the time fear was used for hatred and violence which was used to kill native's so that would also throw out number 2, meaning the only reasonable answer that could be used was number 3, or C they were more susceptible to European disease's, so the colonist would have used that reason in the phrase of, "A sick slave, is not a slave at all, but a burden to our work."

what the first or next guy says