The correct answer is option 1: 1907. In 1907, the Indian National Congress (INC) split between moderates and extremists during its Surat session. This split was a result of ideological differences between the two groups regarding the methods and goals of the independence movement.

The moderates, led by leaders like Dadabhai Naoroji and Gopal Krishna Gokhale, advocated for a cautious and gradual approach towards Indian independence through constitutional means. On the other hand, the extremists, led by leaders like Bal Gangadhar Tilak and Bipin Chandra Pal, believed in more radical and militant methods to achieve independence.

The split at the Surat session created a significant division within the INC and established a clear distinction between the moderates and the extremists. This division had a profound impact on the trajectory of the Indian independence movement.