महाराष्ट्रातील ________ ही सर्वात लांब नदी आहे.

The correct answer is Option D (Godavari).

Key Points:
• The Godavari is the longest river in Maharashtra and the second-longest river in India (after the Ganga).
• Originating at Trimbakeshwar (Nashik) in the Western Ghats, it flows eastwards across the Deccan Plateau.
• Its total length is about 1,465 km, out of which approximately 668 km flows through Maharashtra.
• The Godavari basin covers nearly 49% of Maharashtra's geographical area, making it the most significant river system in the state.
• Key Takeaway: Godavari (668 km in state) is the longest river in Maharashtra, covering 49% of the state's area.