Fundamental duties were added in the constitution of India on the recommendation of

The Fundamental Duties were incorporated into the Indian Constitution by the 42nd Amendment Act of 1976. The Swaran Singh Committee, officially known as the Committee on the Amendment of the Constitution, was formed to suggest changes and amendments to the Constitution. The committee recommended the inclusion of Fundamental Duties to promote a sense of responsibility and civic consciousness among citizens.

Therefore, the correct answer is:
D. Swaran Singh Committee