Explanation:

Let’s break it down:

- Option 1: Humayun Shah

He was a Bahmani ruler, but he's not the one who gave Mahmud Gawan the title of 'Chief of the Merchants' (Malikut-Tujjar).

- Option 2: Alauddin Hasan Bahman Shah

He founded the Bahmani dynasty. His reign established the state, but he isn't the one tied to Mahmud Gawan's famous merchant title.

- Option 3: Muhammad Shah

He ruled a bit earlier than the period that Mahmud Gawan made his mark. So again, not the guy.

- Option 4: Feroz Shah

Now here’s the real answer. Feroz Shah Bahmani was the ruler who granted Mahmud Gawan the title “Malikut-Tujjar,” recognizing his immense contribution, especially in administration and trade.

So, bottom line: Feroz Shah is the one who honored Mahmud Gawan as Chief of the Merchants.