The correct answer is D. All of the above.
Brindaban Ashram was established by Mahatma Gandhi in 1917 in West Champaran district of Bihar, India. It was the first ashram established by Gandhiji in India. The ashram was set up to provide relief to the peasants of Champaran who were suffering from the oppressive indigo plantation system. The ashram also played a role in the Champaran Satyagraha, a major nonviolent protest movement led by Gandhiji.
The All India Gandhi Seva Sangh conference was held at Brindaban Ashram in 1920. The conference was attended by Gandhiji and other prominent leaders of the Indian independence movement. The conference discussed the role of the Gandhi Seva Sangh in the freedom struggle.
Brindaban Ashram is still active today and is a popular tourist destination. The ashram is open to the public and visitors can learn about the life and work of Mahatma Gandhi.