Multiple answers!
select the factors that caused immigration limits to be enforced:

a) the threat of cheap labor to american workers
b) an increase in crime and disease
c) harm to american unity in war times
d) the ku klux klan

I believe A might be correct I’m not sure

Correct answers are A, B, and C.

Explanation:

First off, Ku Klux Klan had nothing to do with immagration. They were " A rural organization that boasted a violent policy of white supremacy."

An Increase in Crime and Disease affected the United States so they had to close off immigration because they believed the cause of this disease came from immigrants.

Harm to the American Unity in war times is also true because while the Americans were busy dealing with war treaties, debts, repair, etc, immigrants kept coming and the Americans thought this to be a big problem.

The Threat of Cheap Labor to American Workers is also true because if immigrants were to work at places, the labor would just be more and more. So, business owners would have to pay more and more to the workers. Also, they would not make enough profit and go bankrupt.

Hope this helped.

russia because it is the biggest state