महाराष्ट्रात सर्वात जास्त सहकारी साखर कारखाने --- जिल्हयात आढळतात.

The correct answer is Option B (Ahmednagar).

Key Points:
• Ahmednagar district is the historical cradle and leading hub of the cooperative sugar movement in Maharashtra and India.
• Asia's first successful cooperative sugar factory—The Pravara Sahakari Sakhar Karkhana—was established at Pravaranagar (Loni) in Ahmednagar district in 1949–50 through the visionary efforts of Padmashri Dr. Vitthalrao Vikhe Patil and Prof. D. R. Gadgil.
• Historically and administratively, Ahmednagar has possessed the highest number of cooperative sugar factories.
• Abundant sugarcane cultivation along the Pravara, Godavari, and Mula river valleys aided rapid proliferation of factories in this district.
• Solapur district has also emerged with a very large number of sugar factories (including many private units), but Ahmednagar remains the classic answer for cooperative sugar industry concentration.
• Key Takeaway: Ahmednagar district has the highest number of cooperative sugar factories in Maharashtra.