Explanation:

- Mehrunnisa, better known as Nur Jahan, married Emperor Jahangir in 1611. This marriage marked a significant period in Mughal history as Nur Jahan became a powerful and influential empress.

- Option 1, 1620: This is incorrect. By this time, Nur Jahan had already been married to Jahangir for several years.

- Option 2, 1602: This is also incorrect. During this year, Mehrunnisa was still married to her first husband, Sher Afghan.

- Option 4, 1603: Incorrect again. Mehrunnisa was widowed this year when Sher Afghan was killed.