The correct answer is: C. Hammir Deva.
Hammir Deva was the ruler of Gujarat when Allauddin Khilji annexed it in 1304. He was a brave and capable ruler, and he fought valiantly against the invading forces. However, he was ultimately defeated, and Gujarat was annexed to the Delhi Sultanate.
Rai Karan was the ruler of Gujarat before Hammir Deva. He was a weak and incompetent ruler, and he was unable to defend Gujarat against the invading forces of Allauddin Khilji.
Ramchandradeva was the ruler of Mewar, a neighboring kingdom to Gujarat. He was a powerful and influential ruler, and he tried to help Hammir Deva defend Gujarat against the invading forces of Allauddin Khilji. However, he was unsuccessful, and Gujarat was annexed to the Delhi Sultanate.
Ratan Singh was the son of Hammir Deva. He succeeded his father as the ruler of Gujarat after his death in 1304. He was a capable ruler, and he tried to regain independence for Gujarat from the Delhi Sultanate. However, he was unsuccessful, and Gujarat remained a part of the Delhi Sultanate until 1573, when it was conquered by Akbar the Great.