Why Correct: Rajendra Chola I launched a northern campaign around 1023-24 CE, reaching the Ganges and defeating the Pala ruler Mahipala I, establishing Chola dominance over Bengal.
Distractor Analysis: Rajaraja I expanded Chola power in South India and Sri Lanka but did not reach Bengal. Rajendra Chola II and Rajadhiraja were later Chola rulers who maintained the empire but did not conquer Bengal.
Takeaway: Rajendra Chola I assumed the title 'Gangaikonda Chola' (the Chola who brought the Ganges) and built Gangaikonda Cholapuram as his new capital to commemorate this campaign.