Answer: a. immigration
Explanation:
a. immigration is the movement of a person from one country/region to another
b. monopoly is the exclusive possession/control of the supply of trade for a certain product/service
c. corporation is a group of people who are legally recognized as a single entity/power and are allowed to act as such
d. political is anything relating to politics, the government, governmental parties, etc.
based on deduction, the answer for this is a. immigration
