Akbar's revenue system known as 'zabt', based on the measurement of land and fixed cash rates, was developed by:

Akbar's revenue system known as "zabt" (or "zabti"), based on the measurement of land and fixed cash rates, was developed by his finance minister, Raja Todar Mal.

About the zabt system:

• NCERT explains that Akbar's revenue minister Todar Mal carried out a careful survey of crop yields, prices and areas cultivated for a ten-year period, from 1570 to 1580.
• On the basis of this data, a tax was fixed on each crop in cash.
• Each province was divided into revenue circles, with its own schedule of revenue rates for individual crops.
• This revenue system was known as zabt.
• It was prevalent in those areas where Mughal administrators could survey the land and keep very careful accounts.
• It was not possible in provinces such as Gujarat and Bengal, where other methods were used.

Main features:

• Land was measured using a standard measure (the gaz-i-Ilahi) and bamboo rods (instead of ropes, which could shrink or stretch).
• The average produce of the land was calculated for each crop.
• The state's share was fixed at about one-third of the average produce.
• The revenue was converted into cash on the basis of average prices.
• The system based on the average of ten years (1570-1580) was also called the "dahsala" system (from "dah", ten, and "sal", year), introduced in 1580.

About Raja Todar Mal:

• He began his career in the service of Sher Shah Suri.
• He joined Akbar's service and rose to become his finance minister (Diwan-i-Ashraf) and one of the most important nobles.
• He was also a capable general, and fought in Gujarat, Bengal and elsewhere.
• He is counted among the "Navaratnas" (nine jewels) of Akbar's court, according to tradition.
• He translated the Bhagavata Purana into Persian, according to some accounts.
• He died in 1589.

Other methods of assessment:

• "Ghallabakhshi" (batai): crop-sharing.
• "Kankut": estimation of the crop.

Why not the other options?

• ✗Birbal was a courtier.
• ✗Abul Fazl was a historian.
• ✗Bairam Khan was Akbar's guardian and regent.