The independent Gujarat Sultanate was founded in the early 15th century by:

Zafar Khan (Muzaffar Shah I)
Ahmad Shah I
Mahmud Begada
Bahadur Shah

The correct answer is Zafar Khan (Muzaffar Shah I).

Zafar Khan (Muzaffar Shah I) was the founder of the Gujarat Sultanate in 1407. He was the son of Alauddin Khalji, the ruler of the Delhi Sultanate. Zafar Khan was appointed the governor of Gujarat by his father in 1396. He rebelled against his father in 1407 and declared himself the Sultan of Gujarat. Zafar Khan ruled Gujarat until his death in 1411.

Ahmad Shah I was the second Sultan of Gujarat. He ruled from 1411 to 1442. Ahmad Shah I was a successful military commander and expanded the territory of the Gujarat Sultanate. He also built many mosques, tombs, and other monuments in Gujarat.

Mahmud Begada was the third Sultan of Gujarat. He ruled from 1458 to 1511. Mahmud Begada was a powerful ruler and expanded the territory of the Gujarat Sultanate to its greatest extent. He also built many forts and palaces in Gujarat.

Bahadur Shah was the fifth Sultan of Gujarat. He ruled from 1526 to 1537. Bahadur Shah was a successful military commander and defeated the Mughal emperor Babur in the Battle of Khanwa in 1527. However, he was defeated by the Mughal emperor Humayun in the Battle of Ghaghara in 1536. Bahadur Shah was killed in the battle.