Step 1: About the Adi Granth Sahib.
The Adi Granth Sahib, compiled by Guru Arjan in 1604 CE, is the central scripture of Sikhism. It contains hymns not only of Sikh Gurus but also of several Bhakti and Sufi saints.
Step 2: Saints included.
- Baba Farid: A famous Sufi saint whose dohas are preserved in the Adi Granth.
- Ravidas: A Bhakti saint from the leatherworking community, who spoke of equality and devotion.
- Kabir: A prominent Bhakti poet-saint whose verses were included to spread the message of devotion and unity.
Step 3: Conclusion.
Since the Adi Granth includes the compositions of Baba Farid, Ravidas, Kabir, along with Sikh Gurus, the correct answer is “All of them.”
\[
\boxed{\text{Correct Answer: All of them}}
\]