The correct answer is option 'D': 15% of landholding and entire Indigo harvest.

Explanation:

Peasants in British India were subjected to various forms of exploitation by British landlords, who were primarily interested in maximizing their profits from the land. One of the ways in which the peasants were exploited was through the imposition of excessive rents and obligations to the landlords.

1. The British landlords demanded a portion of the peasants' landholding as rent. This was a way for the landlords to secure a steady income from the land. The amount of landholding that the peasants had to give as rent varied, but in this case, it was 15% of their landholding.

2. In addition to the rent, the peasants were also required to give a portion of their harvest to the landlords. This was known as the sharecropping system. The landlords would take a percentage of the harvest as their share, and the rest would go to the peasants. In this case, the peasants had to give their entire Indigo harvest to the landlords.

Indigo was an important cash crop during the colonial period, and the British landlords controlled its production and trade. They forced the peasants to cultivate indigo on their land, and the entire harvest was taken by the landlords. This was a highly exploitative practice, as the peasants were left with little to no food for themselves.

The combination of having to give a portion of their landholding as rent and the entire indigo harvest to the landlords put a tremendous burden on the peasants. It left them with very little to sustain themselves and their families. This system of exploitation contributed to the widespread poverty and exploitation of the peasantry in British India.

In conclusion, the peasants in British India had to pay 15% of their landholding as rent and give their entire indigo harvest to the landlords. This system of exploitation placed a heavy burden on the peasants and contributed to their impoverishment.