The Mewar Prajamandal was founded by:-

Concept: Prajamandals (Praja Mandals / Rajya Praja Mandals) were pre-independence political organisations formed by local leaders inside individual princely states — separate from British India's Congress structure — to demand a responsible, representative government under the ruling prince and civil liberties for the state's subjects. Each princely state had its own Prajamandal, founded and led by its own local leaders.

Application: The Mewar Prajamandal (Mewar Rajya Praja Mandal) was founded on 24 April 1938 in the princely state of Mewar (present-day Udaipur region) to demand responsible government under the Maharana of Mewar. Shri Manikya Lal Verma was the principal founder and driving force behind its formation; Balwant Singh Mehta was elected its first President while Verma served as General Secretary. Facing opposition from the state administration, the organisation was declared illegal within months and its activities shifted to Ajmer.

Cross-check: The other names offered are tied to different princely-state organisations, not Mewar:

• Shri Jamnalal Bajaj — a Gandhian industrialist and treasurer of the Indian National Congress, remembered for the Jaipur Rajya Praja Mandal and the Charkha Sangh, not the Mewar body.

• Shri Harimohan Mathur and Shri Brijsunder Sharma — co-founders (19 July 1944) of the Bundi Rajya Lok Parishad, the princely-state people's organisation of Bundi, not Mewar.

Result: RSSB's official answer key for this Patwar 2025 Shift 2 paper also confirms the same. Hence, the Mewar Prajamandal was founded by Shri Manikya Lal Verma.