The Vital-Vidhvansak, the first monthly journal to have the untouchable people as its target audience was published by

Gopal Baba Walangkar (c. 1840-1900), also known as Gopal Krishna, is considered a pioneer in the movement to liberate untouchable people from socio-economic oppression.

In 1888, Walangkar started publishing a monthly journal called Vital-Vidhvansak (Destroyer of Brahmanical or Ceremonial Pollution). This was the first journal specifically aimed at an untouchable audience.

Walangkar also developed a racial theory to explain the oppression faced by lower castes, claiming that high-caste people had foreign origins.

Hence, the correct answer is a.