Final answer:
Guru Nanak Dev Ji became 'Joti Jot' in 1539 at Kartarpur. This event marks his union with the Supreme Being and the end of his earthly journey, which is a significant event in Sikhism.The correct option is A.
Step-by-step explanation:
Guru Nanak Dev Ji, the founder of Sikhism and the first of the eleven Sikh Gurus, became 'Joti Jot' (immersed in the Eternal Light) in the year 1539, at Kartarpur. Kartarpur is a holy site for Sikhs as it was established by Guru Nanak Dev Ji himself and is associated with his final years and teachings. The concept of 'Joti Jot' is significant in Sikhism, reflecting the belief of the soul's return to the divine light, symbolizing the end of one's earthly journey and the completion of their union with the Supreme Being. Thus, the correct answer to the question is A) 1539, Kartarpur.