changing the voting requirements removing candidate age restrictions limiting campaign contributions lowering the voting age
It was primarily "changing the voting requirements" that was proposed by Robert La Follette, since his main stance was that the pre-existing system was skewed.
The correct option is:
Limiting campaign contributions.
As governor of Wisconsin, La Follette established limitations on lobbying activities to end patronage politics. His progressive legislation included also measures to make direct primary elections, projects that increased the taxes on the railroads, attack monopolies, protected the state's forests, defended small farmers and workers' rights.