The correct answer is option 'C' - the feudatory princes.

Explanation:

The Indian Rebellion of 1857, also known as the Sepoy Mutiny or the First War of Independence, was a widespread uprising against the British East India Company's rule in India. It was a significant event in Indian history and had a profound impact on the country's political, social, and cultural landscape.

During the rebellion, several sections of Indian society were involved, including soldiers, peasants, artisans, and intellectuals. However, there were some groups that chose to stay away from the political upsurge and instead rendered memorable service to the British. One such group was the feudatory princes.

1. Feudatory Princes:
- The feudatory princes were the rulers of various princely states in India, who held a subordinate position under the British colonial administration.
- These princes were not directly under the control of the East India Company and enjoyed some autonomy in their territories.
- During the rebellion of 1857, many of these feudatory princes remained loyal to the British and provided crucial support in suppressing the uprising.
- They offered military assistance, resources, and safe havens to the British forces, enabling them to maintain control over their territories.
- The British rewarded the loyalty of these princes by granting them various privileges and concessions, such as increased autonomy, territorial integrity, and recognition of their titles and privileges.

2. Middle Class and Backward Castes:
- The middle class, comprising professionals, merchants, and educated individuals, played a significant role in the Indian independence movement but did not remain aloof from the political upsurge of 1857.
- They actively participated in the rebellion, providing leadership, financial support, and intellectual guidance to the movement.
- Similarly, the backward castes, including peasants and lower-caste communities, were also actively involved in the rebellion, driven by grievances related to land rights, oppressive taxation, and social discrimination.

In conclusion, while the middle class and backward castes actively participated in the rebellion of 1857, it was the feudatory princes who not only kept aloof from the uprising but also rendered memorable service to the British. Their loyalty and support were instrumental in helping the British suppress the rebellion and maintain their control over India.