Option b is the correct answer. Shahab Nahr was constructed by restoring the Rajabwah of Firoz Shah. The canal carried water from the Yamuna River and extended from the river Satluj to Jhajjar. It was part of a network of canals that served to bring water to various regions during the Mughal period. Important Tips Firoz Shah Tughlaq (1351 AD-1388 AD): Firoz Shah Tughlaq undertook the restoration of canals and introduced the Haque-i-Sharb or Hasil-i-Sharb, a water tax system. He is considered the "father of the irrigation system in India" for his efforts in channelizing rivers and providing water through canals to various regions of the country. His reign witnessed the segregation of Jizya as a distinct tax, alongside other taxes like Kharaj, Zakat, and Khams, all based on Quranic principles. Firoz Shah's contributions extended to social welfare with the establishment of a hospital in Delhi, earning him the title Darul-Shifa. Notably, he authored the Tarikh-i-Feroshahi and Fatwa-i-Jahangiri, reflecting his interests in historical documentation and legal matters.