Explanation:

- In February 2019, the prestigious Makran Cup was held in Chabahar, Iran.

- This boxing tournament featured many talented athletes competing for top honors.

- Deepak Singh clinched a gold medal at this event.

- This victory was significant in his sports career.

- Option 1, Manish Kaushik is known for his achievements in boxing, including participating in the Olympics, but he didn't win at this event.

- Option 2, Rohit Tokas is another Indian boxer with accolades in other competitions, but not at the Makran Cup.

- Option 4, Satish Kumar is a heavyweight boxing star but didn't secure a gold medal in this specific tournament.