Important Battles question: In which year did Nadir Shah defeat the Mughal Emperor Muhammad Shah at the Battle of Karnal?

The source-backed, question-specific record explains: The Battle of Karnal was fought on February 13 1739 between the Persian invader Nadir Shah and Mughal Emperor Muhammad Shah. Nadir Shah won and subsequently sacked Delhi taking the Peacock Throne and Koh-i-Noor diamond. This evidence establishes the historical relationship required in this Important Battles item. A correct solution must preserve the exact battle, date, participants, commander, location, outcome or significance requested by the stem. Similar periods, genres or national traditions do not make two battle facts interchangeable. Option A gives 1739 and satisfies every condition stated in the question. The remaining choices—1761, 1757 and 1526—do not satisfy the complete requirement. The reliable checking method is to identify the named battle first, recall or verify its verified participant or outcome, and then read qualifiers such as “both works,” “original language,” “first published,” “correctly matched” or “incorrectly matched.” These qualifiers determine what counts as the answer. Replaying that method for this Important Battles question confirms 1739 without relying on option position.