The irrigation tax was charged on the farmers for the first time by which among the following Sultans?
[A] Alauddin Khilji
[B] Ghiyasuddin Tughlaq
[C] Mohammad Tughlaq
[D] Firoz Tughlaq

Firoz Tughlaq
Firoz Shah Tughlaq was the cousin brother of Muhammad Bin Tughlaq, and became the ruler of Delhi on 23rd march 1351 A.D. He imposed only four taxes sanctioned by Islamic viz., kharaj (land tax), khams (1/5 of the looted property during wars), Jizya (religious tax on the Hindus), and Zakat (2½per cent of the income of the Muslims which was spent for the welfare of Muslim subjects and their religion). He imposed irrigation tax after getting it sanctioned from the Ulema.