Final answer:
In the early twentieth century, Australia tried to exclude certain groups of immigrants, including the Irish people.
Step-by-step explanation:
The correct answer is c) Irish people. In the early twentieth century, Australia implemented policies to exclude certain groups of immigrants, including the Irish. These policies were motivated by a desire to maintain a predominantly white, European population in Australia. The Australian government aimed to attract immigrants from northern European countries while restricting immigration from other parts of the world.