What was the main reason for the split in the Indian National Congress…

Introduction of communalism into Indian politics by Lord Minto
Extremists' lack of faith in the capacity of the moderates to negotiate with the British Government
Foundation of Muslim League
Aurobindo Ghosh's inability to be elected as the President of the Indian National Congress

Answer

Extremists' lack of faith in the capacity of the moderates to negotiate with the British Government

(a) Lord Minto's policies and separate electorates relate more to later communal politics, not the immediate cause of the Surat split in 1907. Verdict: Incorrect.
(b) The split was mainly due to the growing conflict between Moderates and Extremists; Extremists had lost faith in the Moderates' constitutional methods and ability to secure concessions from the British. Verdict: Correct.
(c) The Muslim League was founded in 1906, but this was not the main reason for the Congress split at Surat. Verdict: Incorrect.
(d) The Surat session controversy centered on the presidentship issue involving Rash Behari Ghosh, not Aurobindo Ghosh's failure to be elected. Verdict: Incorrect.