The correct answer is **Sindu, Ganga and Brahmaputra** (Option 3). **Comprehensive Derivation:** The correct answer is Sindu, Ganga and Brahmaputra Explanation & Key Takeaways: • The correct group of rivers that contributed to the formation of the northern plains of India is: Sindu (Indus), Ganga (Ganges), and Brahmaputra. • These three rivers - the Indus, Ganges, and Brahmaputra - along with their tributaries, carried an enormous amount of sediment down from the high and steep slopes of the Himalayas. • Over millions of years, these sediments filled the trough between the peninsular plateau and the northern mountains of India, forming the northern plains, also known as the Indo-Gangetic Plains. • The constant deposit of alluvial soil regularly renewed the fertility of the soil. • This deposition took place mainly due to the recurring floods, making the northern plains one of the most fertile regions in the world. • It has led to a high population density in the region because of the resulting agricultural productivity. • These rivers dividing into multiple river channels also contributes to the formation of the plains. • The Brahmaputra, in particular, is known for creating vast floodplains due to annual flooding and river bifurcation. • These processes caused the distribution of sediments across a broad area, helping in the formation and expansion of the plains. **Option Elimination:** • **Option 1 (Ganges, Yamuna and Godavari)**: Incorrect distractor. • **Option 2 (Yamuna, Ganga and Mahanadi)**: Incorrect distractor. • **Option 3 (Sindu, Ganga and Brahmaputra)**: Correct Answer; accurate according to canonical reference. • **Option 4 (Brahmaputra, Mahanadi and Godavari)**: Incorrect distractor. **Exam Trap:** Be careful of misleading distractors and subtle terminology differences. Verify core properties before selecting your answer. **Memory Booster:** Core mnemonic rule: Sindu, Ganga and Brahmaputra corresponds to Option (3).