It would be "d. eight-hour days" that was not a problem faced by workers in nineteenth century mills or mines, since legislation advocating for strict working hours did not come about until the Progressive Era.
Answer:
Separation of powers is a doctrine of constitutional law under which the three branches of government (executive, legislative, and judicial) are kept separate. This is also known as the system of checks and balances, because each branch is given certain powers so as to check and balance the other branches.
