The county unit system was eventually declared invalid because

a) people should not have to vote in the county where they reside.
b) under the system african americans controlled most votes.
c) every person’s vote should be given equal weight.
d) the federal government became involved.

A- every person’s vote should be given equal weight.

Explanation:

The County Unit System was eventually declared invalid because every person’s vote should be given equal weight. The federal government felt that this was a state issue, so they would not address the problem.

I took the test aka usatestprep

c holding free elections

d. it spread christianity. i just took the test and got it right.