The correct option is B He was summoned by Aurangzeb to resolve a dispute over the Guruship.
Guru Har Krishan Ji travelled to Delhi to meet the emperor Aurangzeb. He was summoned by the diplomatic ruler to resolve an issue over the Guruship between him and his brother Ram Rai. Ram Rai was not given the Guruship because he changed the meaning of a Gurbani to satisfy Aurangzeb. When the Bal Guru visited Delhi, he found that it was plagued with smallpox and cholera. He contracted the disease himself in the effort to save others and ultimately succumbed to it. However, his brother did not attain Guruship following his death. Instead, Guru Har Krishan Ji named Guru Tegh Bahadur Ji of Bakala village as his successor.