The correct option is B Grandson of Firoz Shah
Firoz Shah was succeeded by one of his grandsons, Tughlaq Shah. He eventually assumed the name Ghiyasuddin Tughlaq II. But within a year, he died and the Sultanate fell into political instability. The last ruler of the Tughlaq dynasty was Nasiruddin Mahmud Shah Tughlaq. During his rule, Timur, the Mongol leader of Central Asia invaded India in 1398. This came as a fatal blow to the Tughlaqs.