Answer: d. Congressional districts were made similar in population size.
Step-by-step explanation:
The case in question is known as Wesberry v. Sanders and was given judgement by the Supreme Court in 1964. In it, the Supreme Court stated that Congressional districts should similar in population size.
The number of seats that a state gets in Congress is proportional to its population but within the state, the State was free to draw up districts that divided the population of the whole state as it saw fit.
This led to a situation where some districts would have more population than the others and allowed for uneven voting. The Supreme Court ruled that this was unconstitutional because the Constitution implies that votes in the United States should have equal worth.