Who served as the president of the All India Depressed Classes Conference held in the year 1930?

The correct option is B. R. Ambedkar.

Explanation:
In August 1930, the All India Depressed Classes Conference was organized in Nagpur. Dr. B. R. Ambedkar presided over this historic conference, which served as a landmark event in the struggle for the political and social rights of the marginalized classes in India.

Key Historical Context & Significance:
1. Presidential Address: During his presidential address, Dr. B. R. Ambedkar articulated a clear vision for the socio-political emancipation of the depressed classes, emphasizing that genuine freedom could only be achieved if all sections of society enjoyed equal political power and dignity.
2. Political Safeguards: He strongly advocated for constitutional safeguards, direct political representation, and special provisions (such as separate electorates) to ensure that the interests of the depressed classes were protected in future governance frameworks.
3. National Impact: The 1930 conference formally established Dr. B. R. Ambedkar as the prominent national spokesperson for the depressed classes and laid the foundation for subsequent negotiations, including his participation in the Round Table Conferences.

Therefore, Dr. B. R. Ambedkar was the president of the All India Depressed Classes Conference held in the year 1930.