The Prathana Samaj was a socio-religious reform movement that emerged in the 19th century in Bombay (now Mumbai), India. It aimed to bring about social and religious reforms in Hindu society. The movement laid stress on various issues like widow remarriage, female education, abolition of child marriage, purdah, and the abandonment of caste. The correct answer to the question is option 'E' - all of the above.

Introduction of Widow Remarriage and Encouragement to Female Education:
- The Prathana Samaj strongly advocated for the introduction of widow remarriage in Hindu society.
- In traditional Hindu society, widow remarriage was considered taboo and widows were often subjected to social ostracism and neglect.
- The movement sought to challenge these social norms and provide opportunities for widows to remarry and lead a fulfilling life.
- Additionally, the Prathana Samaj emphasized the importance of female education. It believed that educating women would empower them and enable them to contribute to the progress of society.

Abolition of Child Marriage and Purdah:
- The Prathana Samaj also aimed to eliminate the practice of child marriage, which was prevalent in Hindu society.
- Child marriage was detrimental to the physical and mental well-being of young girls, and the movement sought to raise awareness about its harmful effects.
- Purdah refers to the practice of women covering themselves and maintaining seclusion in public spaces. The Prathana Samaj sought to abolish this practice as it restricted women's freedom and participation in society.

Abandonment of Caste:
- The Prathana Samaj strongly believed in the unity and equality of all individuals, irrespective of their caste or social status.
- It advocated for the abandonment of caste and worked towards creating a society where caste-based discrimination and untouchability were eradicated.
- The movement aimed to promote a sense of brotherhood and equality among all members of society.

In summary, the Prathana Samaj laid stress on various social and religious reforms, including widow remarriage, female education, abolition of child marriage and purdah, and the abandonment of caste. These reforms were aimed at bringing about a more progressive and egalitarian society.