The correct answer is (b) Paibaqi.
Paibaqi was the unassigned jagir lands managed temporarily by the Diwan-i-Khalisa. It was a system of land revenue administration in the Mughal Empire. The Diwan-i-Khalisa was the department of the Mughal government that was responsible for collecting land revenue. Paibaqi lands were those that were not assigned to any specific jagirdar or revenue collector. They were managed directly by the Diwan-i-Khalisa and the revenue from them was used to meet the expenses of the central government.
The other options are incorrect.
(a) Peshkash was a form of tribute that was paid by the Mughal emperors to the Safavid Empire.
(c) Madad-e-Mash was a system of land grants that were given to religious scholars and other learned men.
(d) Ghurab was a type of tax that was levied on the sale of horses.