Who among the following was a proponent of Fabianism as a movement?

Annie Besant was an active proponent of Fabianism: she is listed among early Fabian contributors and is documented as joining the Fabian Society in the mid-1880s, participating in its socialist reform efforts [2]. The other options do not fit Fabian affiliation: A. O. Hume is best known for founding the Indian National Union which became the Indian National Congress, not for Fabian politics [3]. R. Palme Dutt (Rajani Palme Dutt) was associated with revolutionary/communist circles rather than the gradualist Fabian approach [4]. Michael Madhusudan Dutt was a 19th‑century Bengali poet and dramatist, not a Fabian activist. Thus the correct answer is Annie Besant.

Sources

1. [1] https://fabians.org.uk/about-us/our-history/
2. [2] https://www.secularism.org.uk/annie-besant
3. [3] Rajiv Ahir. A Brief History of Modern India (2019 ed.). SPECTRUM. > Chapter 11: Indian National Congress: Foundation and the Moderate Phase > Summary > p. 256
4. [4] https://library.bjp.org/jspui/bitstream/123456789/720/1/M.%20K.%20Singh%20-%20Freedom%20Movemement%20Encyclo.vol11.pdf