Rohtas fort was built in Pakistan during the rule of:

The correct answer is C. Sher Shah Suri. The magnificent Rohtas Fort, a UNESCO World Heritage site located in Pakistan, was constructed by the Pashtun emperor Sher Shah Suri between 1541 and 1548 CE. Its primary purpose was to defend against the return of the Mughal emperor Humayun, whom Sher Shah had defeated, and to subdue the local Gakhar tribes who were loyal to Humayun. The fort's massive defensive walls and strategic location exemplify Suri architecture and military engineering. Babar, the founder of the Mughal Empire, and his son Humayun ruled earlier and later, respectively, and were not associated with the construction of Rohtas Fort. This fort stands as a testament to Sher Shah Suri's brief but impactful reign, characterized by significant administrative and architectural achievements.