Zakat tax was imposed by the Muslim rulers on Muslims.

Explanation:

1. Introduction to Zakat:
Zakat is an Islamic concept of giving a specific portion of wealth to the less fortunate members of society. It is considered one of the Five Pillars of Islam and is obligatory for all financially capable Muslims. The Quran mandates the payment of Zakat as a means of assisting the poor and promoting social welfare.

2. Imposition of Zakat tax by Muslim rulers:
a) Justification: Muslim rulers imposed Zakat tax on Muslims as a way to ensure the fulfillment of their religious duty. It was seen as a means to regulate the collection and distribution of Zakat funds, ensuring that the wealthier Muslims fulfill their obligation towards the less fortunate.

b) Collection: The rulers appointed officials known as 'amil' to collect Zakat from the Muslim population. These officials were responsible for identifying eligible recipients and overseeing the distribution of Zakat funds.

c) Assessment: The amount of Zakat tax to be paid was determined based on the individual's wealth and assets. This assessment was done by the appointed officials who would calculate the eligible amount on which Zakat was due.

d) Utilization: The Zakat funds collected were utilized for various purposes, including providing financial assistance to the poor, supporting orphans and widows, funding education and healthcare initiatives, and promoting social welfare projects.

3. Exemption for non-Muslims:
The Zakat tax was specifically imposed on Muslims, and non-Muslims, such as Rajputs and Brahmins, were exempt from this obligation. This exemption was based on the Islamic principle that Zakat is a religious duty specifically mandated for Muslims.

4. Significance and impact:
The imposition of Zakat tax by Muslim rulers played a crucial role in promoting social justice and welfare within the Muslim community. It helped in redistributing wealth, reducing inequality, and addressing the needs of the less privileged.

Conclusion:
Zakat tax was imposed by Muslim rulers on Muslims to ensure the fulfillment of their religious obligation towards the less fortunate. Non-Muslims, such as Rajputs and Brahmins, were exempt from this tax as it was specifically mandated for Muslims. The imposition of Zakat tax played a significant role in promoting social welfare and reducing inequality within the Muslim community.