Consider the following statements regarding the social and religious reform movements and their founders/leaders in 19th-century India:

1. 1. The primary objective of the 'Brahmo Samaj', established by Raja Ram Mohan Roy in 1828, was to establish monotheism based on the non-dualistic (Advaita) philosophy of the Upanishads while refuting evil practices such as idol worship, polytheism, and the Sati system.
2. 2. The 'Arya Samaj', founded by Swami Dayanand Saraswati in 1875, gave the slogan 'Back to the Vedas' and initiated the 'Shuddhi Movement' to purify Hindu society and bring back converted Hindus into the fold of Hinduism.
3. 3. The main objective of the 'Satyashodhak Samaj', established by Jyotirao Phule in 1873, was to liberate lower castes (Shudras and Atishudras) from Brahmanical dominance and religious hypocrisy while securing social justice for them.
4. 4. The 'Prarthana Samaj', established by Atmaram Pandurang in 1867 under the inspiration of Keshab Chandra Sen, laid special emphasis on social reforms such as inter-caste marriage, widow remarriage, women's education, and the upliftment of Dalits, while never attempting to completely separate itself from orthodox Hinduism.

Which of the above statement(s) is/are completely true?