The correct option is A He invited a Muslim Sufi saint to lay the cornerstone for the Harmandir Sahib.
Guru Arjan Dev Ji was religiously tolerant. He constructed the Golden Temple with four entrances to symbolise the acceptance of all religions. Guruji invited the Muslim Sufi saint, Mian Mir from Lahore, to lay the cornerstone of the foundation for the Harmandir Sahib in 1588. He rejected his son's marriage to Chandu Shah's daughter because Shah was an egoistic man and Guruji disliked his nature.