The correct answer is: D. 1739 AD
The Battle of Karnal was fought on 13 February 1739, near Karnal in the present-day Indian state of Haryana. The battle was fought between the Mughal Empire under the command of Muhammad Shah and the invading Persian army of Nader Shah. The Persians were victorious, and Muhammad Shah was captured. The battle marked the beginning of the decline of the Mughal Empire.
Option A: 1723 AD is incorrect. The Battle of Karnal did not take place in this year.
Option B: 1789 AD is incorrect. The Battle of Karnal did not take place in this year.
Option C: 1756 AD is incorrect. The Battle of Plassey took place in this year, not the Battle of Karnal.
Option D: 1739 AD is correct. The Battle of Karnal took place in this year.