Answer:
Option D: Burr's belief that Hamilton had slandered him.
Explanation:
The duel stemmed from a history of animosity between both men over the years. The existing personal animosity and personal bitterness between both individuals came to a head in the run-up to the governorship election in New-York in 1804.
The Albany Registrar published a letter sent from Charles Cooper to senator Philip Schuyler which referenced a statement made by General Hamilton describing Colonel Burr as being a dangerous and despicable human being incapable of running a government.
The ensuing duel was as a result of this defamation.