The appointment of a colony's governor-general by the colonial power is an example of
a. imperialism
b. direct rule
c. indirect rule
d. a combination of indirect and direct rule

I would go with indirect rule or letter c. because there is a representative who is now in charge of governing the colony but he still has to present what is needed for things to run smoothly.  It can also be imperialism or letter a.  because where the rule is direct or indirect, that country is now controlled or under the influence of a foreign power.

b. Direct rule.

Explanation:

Direct rule is when a central power has direct control over the parliament, executive and civil authority of an otherwise self-governing nation.

Direct colonial rule was a certain kind of colonialism that required the institution of a centralized external power within a colony, which was controlled by colonial administrators. The local community was usually banned from most levels of the colonial administration.

aliens arent real sorry bud