The Catholic Church(aka the Roman Catholic Church) did NOT have its own court system. so the answer is...D
A) "Was originally in favor of slavery, but now is that party that is viewed as championing rights of minorities." In fact, they were in favor of slavery, and nowadays they look after minority groups such as immigrants, women, African Americans, etc.
C) "Had the only presidential candidate that was elected for three consecutive terms.". Franklin Delano Roosevelt was elected President for three consecutive terms.
D) "Held control of the Senate for over 30 years." The Democratic party has controlled the Congress and the White House for over 30 years in the past 100 years.
The judicial branch enforces the law; making sure it is carried out and people oblige to it. They also determine if the policy is constitutional or unconstitutional.
People had the most power due to the government being afraid they would have too much power (the reason why they left in the first place).