Answer:
3.infection
Step-by-step explanation:
The colonialists did use many things to influence and even control native societies.
They used trade to give them simple things they did not have in exchange for valuable things that the colonialists needed or wanted.
They used religion to control their behavior.
They even used the military when it would come down to who had more power.
Infection, though, was not a tool of the colonialists and it actually makes little to no sense.