With reference to Indian history, consider the following statements: The first…

Mongol incursions into the Indian subcontinent were not a single episode but a recurring frontier threat that ran across several Delhi Sultanate dynasties. Evaluating a set of statements about "the first invasion", a specific ruler's encounter, and a claimed territorial loss requires placing each ruler's reign on this timeline and checking the claim against the historically recorded events of that reign, not against the dynasty's general reputation.

1. The Mongol threat to India began earlier than the Khalji period: the first recorded Mongol incursion reached the Indus in 1221-22, during Iltutmish's reign (Delhi's Mamluk/"Slave" dynasty), when Chinggis Khan pursued the fleeing Khwarazmian prince Jalal-ud-din Mangburni to the river's banks; Iltutmish avoided engaging the Mongols directly and refused Mangburni asylum. This predates Jalal-ud-din Khalji (founder of the later Khalji dynasty, r. 1290-1296) by roughly seven decades, so placing the first invasion in his reign misplaces the timeline.

2. Ala-ud-din Khalji's reign (1296-1316) faced the heaviest and most sustained Mongol pressure of the Sultanate period. Among several raids, the 1303 assault led by the Mongol commander Targhi, serving under Chagatai Khan Duwa, reached the outskirts of Delhi and besieged the city for close to two months while Ala-ud-din fortified himself at Siri.

3. Muhammad-bin-Tughlaq's reign (1325-1351) did face a serious north-west frontier crisis: Tarmashirin Khan's invasion around 1327-28 overran forts near Lahore, Samana, and Indri and pushed into the Doab before the Sultan's forces drove the Mongols back. That episode is standardly read as a repulsed raid, not as a lasting or even temporary cession of north-western territory to the Mongols, so the claim that the Sultanate actually lost part of the region does not match the accepted account.

• The combination pairing the first two claims joins a chronologically displaced event (really an Iltutmish-era encounter) with a well-attested Ala-ud-din-era siege.

• The combination pairing the first and third claims joins the same displaced event with an unattested territorial-loss claim.

• Isolating only the third claim still rests on an unattested territorial-loss claim.

Checking each claim independently against the reign-by-reign timeline, rather than treating "Mongol invasion" as one undifferentiated fact spread evenly across the Sultanate period, is what separates the well-evidenced claim from the other two.

Statement 1 is therefore false, statement 2 is true, and statement 3 is false -- so only statement 2 is correct, and "2 only" is the accepted answer.