Mahadev Govind Ranade was primarily associated with the:

Prarthana Samaj

The correct answer is Option 3- Prarthana Samaj.

Mahadev Govind Ranade was a founding member of the Prarthana Samaj, a reformist Hindu organization that was founded in 1867 in Mumbai. The Prarthana Samaj advocated for social reform, such as the abolition of child marriage, the remarriage of widows, and the education of women.

Ranade was a strong advocate for social reform and he believed that the Prarthana Samaj could play a leading role in bringing about change in Indian society. He was also a prolific writer and he wrote extensively on social reform, economics, and history.

The other options are incorrect:

• The Arya Samaj is a reformist Hindu organization that was founded in 1875 in Lahore. It is known for its promotion of Vedic religion and culture.
• The Sadharan Brahmo Samaj is a reformist Hindu organization that was founded in 1878 in Calcutta. It is known for its advocacy of monotheism and social reform.
• Brahmo Samaj is a general term for reformist Hindu organizations that advocate for monotheism and social reform.