The correct answer is: A. Nader Shah and Shah Alam.
The Battle of Karnal was fought on 13 February 1739, near Karnal in the Indian subcontinent, between the Iranian army of Nader Shah and the Mughal army of Muhammad Shah. The battle was a decisive victory for Nader Shah, who captured the Mughal emperor and plundered the Mughal capital of Delhi.
Nader Shah was the ruler of Persia from 1736 to 1747. He was a skilled military commander and a ruthless conqueror. He expanded the Persian Empire to include parts of modern-day Iran, Afghanistan, Pakistan, India, and Central Asia.
Muhammad Shah was the Mughal emperor from 1719 to 1748. He was a weak and incompetent ruler. He was unable to control his empire, which was falling apart under the pressure of internal rebellions and external invasions.
The Battle of Karnal was a turning point in the history of India. It marked the end of the Mughal Empire and the beginning of the decline of Indian power.
Option B is incorrect because Muhammad Shah was the Mughal emperor at the time of the battle, not Nader Shah.
Option C is incorrect because Shah Alam was the Mughal emperor who succeeded Muhammad Shah. He was not involved in the Battle of Karnal.
Option D is incorrect because Aurangzeb was the Mughal emperor who ruled before Muhammad Shah. He died in 1707, 32 years before the Battle of Karnal.