The title Ambassador of Hindu–Muslim Unity was given to Jinnah by

Historical titles often encapsulate a leader's significant contributions and public perception during a particular era. Muhammad Ali Jinnah, the founder of Pakistan, was initially known for his efforts to foster unity between India's two major communities.

• The correct answer is Sarojini Naidu. The esteemed Indian poet and political activist, Sarojini Naidu, famously conferred the title "Ambassador of Hindu-Muslim Unity" upon Muhammad Ali Jinnah. She did so in her 1917 biographical sketch, "Mohammad Ali Jinnah: An Ambassador of Unity." This recognition came during Jinnah's early political career when he was a strong proponent of Hindu-Muslim cooperation and played a crucial role in the Lucknow Pact of 1916.
• Option B, Allama Iqbal, is incorrect; while a key figure, he did not give Jinnah this specific title.
• Option C, Jawaharlal Nehru, is incorrect; as a political contemporary and later rival, he would not have bestowed such an honor.
• Option D, None of these, is false.

This title highlights a crucial phase of Jinnah's political journey.