Step 1: Historical context.
The Second Battle of Panipat was fought in 1556, after Humayun’s death. The Mughal throne had passed to the young Akbar, while Hemu (a capable general of Adil Shah Suri) attempted to seize power.
Step 2: The battle.
- Hemu had captured Delhi and declared himself ruler.
- Akbar, under the guidance of Bairam Khan, marched to reclaim Mughal authority.
- The armies clashed at Panipat in 1556.
Step 3: Outcome.
Hemu was defeated when he was struck by an arrow in the eye, causing panic among his troops. This decisive victory secured the Mughal empire for Akbar.
Step 4: Elimination of wrong options.
- (B) Ibrahim Lodi: Defeated by Babur in the First Battle of Panipat (1526), not Akbar.
- (C) Nadir Shah: Invaded India in 1739, long after Akbar’s time.
- (D) Bajirao: Maratha leader of the 18th century, not contemporary to Akbar.
Step 5: Conclusion.
Thus, in the Second Battle of Panipat (1556), Akbar defeated Hemu.
\[
\boxed{\text{Correct Answer: Hemu}}
\]