Timur invaded India and ordered a general massacre of people of Delhi during the reign of __________?
1) Nasir-ud-din Mahmud
2) Ghiyasuddin II
3) Abu Bakr
4) Alauddin Sikandar

Hint: The Mamluk dynasty ( \[1206-1290\]), the Khalji dynasty\[\left( {1290-1320} \right)\], the Tughlaq dynasty \[\left( {1320-1414} \right)\], the Sayyid dynasty \[(1414-1451)\], and the Lodi dynasty \[\left( {1451-1526} \right)\] were the five dynasties that governed the Delhi Sultanate in succession.

Complete answer:
Timur, also known as Amir Timur or Tamerlane, was a Turco-Mongol conqueror who established the Timurid Empire in and around modern-day Afghanistan, Iran, and Central Asia. Timur attacked the Delhi Sultanate, which was ruled by Sultan Nasir-ud-Din Mahmud Shah Tughluq of the Tughlaq dynasty, in $1398$. On $30$ September $1398$, he sacked Tulamba and massacred its inhabitants after crossing the Indus River.

Then he advanced and, by October, had captured Multan. Most of the Indian aristocracy surrendered without a fight, but he did face opposition from a combined army of Rajputs and Muslims under the command of Rao Dul Chand at Bhatner. The Rao initially opposed Timur, but when pressed, he considered surrendering. The majority of the Indian aristocracy surrendered without a fight, but he did face resistance at Bhatner from a joint army of Rajputs and Muslims led by Rao Dul Chand. When pushed, the Rao considered surrendering, despite his initial opposition to Timur.

Timur's march towards Delhi was hampered by the Jat peasantry, who looted caravans and then vanished into the woods. Timur killed $2,000$ Jats and kidnapped many more. The Sultanate of Delhi, on the other hand, did little to halt his progress.

The correct answer is Nasir-ud-din Mahmud.

Note: From $1394$to $1397$, the last rulers of this dynasty were Nasir ud-Din Mahmud Shah Tughlaq, the grandson of Firuz Shah Tughlaq, who ruled from Delhi, and Nasir ud-Din Nusrat Shah Tughlaq, a relative of Firuz Shah Tughlaq, who ruled from Firozabad, a few miles from Delhi.