Concept:Baytul Mal is the Islamic public treasury, and its funds must come only from legitimate sources of revenue allowed by Shariah.
Explanation:Kharaj is an Islamic tax imposed on agricultural land and its produce.
It was collected from non-Muslim subjects of the Islamic state.
During early Islamic rule, Kharaj was a major source of funds for Baytul Mal.
Amanah means a trust or deposit, so it is not treated as income for the treasury.
Riba refers to interest or usury, which is strictly prohibited in Islam and cannot fund the treasury.
Tatfif means giving short measure or weight, which is a sin and not a legal source of revenue.
Therefore, among the options, Kharaj is the correct source of funds for Baytul Mal.
Answer:B. Kharaj