The correct answer is option 'C', the Kherwar or Sapha Har movement.

The Kherwar or Sapha Har movement was a socio-religious movement that originated in the Kherwar region of Bihar in the early 19th century. It was led by a tribal religious leader named Bisra Munda. The movement initially preached monotheism and focused on internal social reforms within the tribal community.

Preaching Monotheism and Internal Social Reform:
- The Kherwar movement emphasized the worship of a single God and rejected the worship of multiple deities.
- It aimed to eradicate superstitions and practices like animal sacrifices among the tribal people.
- The movement also advocated for social equality and opposed caste-based discrimination.
- It sought to uplift the status of women in society and discourage practices like child marriage.

Campaigning Against Revenue Settlement Operations:
- The Kherwar movement gradually shifted its focus from religious reforms to socio-economic issues.
- It started campaigning against the revenue settlement operations conducted by the British colonial administration.
- The revenue settlement operations involved the assessment and collection of land revenue from the local population.
- The movement criticized the excessive taxation imposed by the British, which often led to the exploitation of the tribal communities.
- The Kherwar leaders mobilized the tribal people and organized protests against the revenue settlement operations.

Suppression of the Movement:
- The British authorities viewed the Kherwar movement as a threat to their colonial rule and suppressed it.
- Bisra Munda, the leader of the movement, was arrested and imprisoned.
- The movement was forcibly disbanded, and its followers were subjected to repression and persecution.

In conclusion, the Kherwar or Sapha Har movement initially focused on preaching monotheism and internal social reform within the tribal community. However, it later shifted its focus towards campaigning against the revenue settlement operations conducted by the British colonial administration. This shift in focus ultimately led to the suppression of the movement by the British authorities.