According to Jyotiba Phule, which of the following statements is correct?

a. Jyotiba Phule is one of the earliest leaders of the non-Brahmin movement.

b. He founded Satyashodhak samaj which supported the upliftment of women, the depressed class, and the caste system.

c. The word "Dalit" for depressed classes was first used by him.

d. Shetkaryacha Asud was written by him.