Which of the following describes the way reform was brought to Tammany Hall?

A.
Inside leaders such as Charles Murphy launched their own reform efforts.

B.
Aggressive muckrakers such as Upton Sinclair undermined their control.

C.
Political upstarts such as Hazen Pingree used democracy to overwhelm the machine.

D.
Intellectuals such as Grover Cleveland united businessmen with reform groups.

To determine the correct answer, let's break down the options:

A. Inside leaders such as Charles Murphy launched their own reform efforts: This suggests that individuals within Tammany Hall itself initiated and implemented reforms.

B. Aggressive muckrakers such as Upton Sinclair undermined their control: This option implies that investigative journalists exposed the corruption and wrongdoing of Tammany Hall, leading to its loss of power.

C. Political upstarts such as Hazen Pingree used democracy to overwhelm the machine: This option suggests that new and emerging political figures used democratic processes to challenge Tammany Hall and bring about reform.

D. Intellectuals such as Grover Cleveland united businessmen with reform groups: This option proposes that intellectuals, in collaboration with business interests and reform-minded groups, were instrumental in bringing about reform in Tammany Hall.

By considering the nature of reform and the role different actors played, we can eliminate options A and B. Reform efforts initiated from within Tammany Hall were unlikely, given the deeply entrenched corruption. Similarly, aggressive muckraking might have exposed corruption but would not have directly brought about reform.

Option C suggests that political upstarts used democratic means to overcome the machine's influence, which aligns with the general idea of democratic processes promoting reform.

Option D indicates that intellectuals, in conjunction with businessmen and reform groups, played a role in bringing about change. However, Grover Cleveland's association with the reform movement may not be accurate regarding Tammany Hall specifically.

Considering these factors, it is most likely that the correct answer is C. Political upstarts such as Hazen Pingree used democracy to overwhelm the machine.