Final answer:
Progressives would not support the idea of 'Party bosses in power' as they sought to dismantle the influence of party bosses to foster a more democratic and accountable government.
Step-by-step explanation:
The idea that Progressives would not support among the options provided is C. Party bosses in power. Progressives aimed to make government more responsive to the will of the people and end political corruption. They wanted to dismantle the power of party bosses and ensure a democratic system where voters could have a direct say on legislation and officials.
In contrast, social, business, and government reforms were fundamental to the Progressive ethos, as they targeted political corruption, corporate accountability, and social injustice, respectively.