Which one of the following is a language of Baluchistan but linguistically Dravidian ?

The Dravidian language family is principally concentrated in southern India and is described as the Dravidian family in standard references [1]. Despite this southern core, one Dravidian language is spoken far to the west: Brahui, which is attested as a Dravidian language spoken in Balochistan (and Sindh) of Pakistan and is classed among the northern Dravidian varieties in major references [3]. Therefore, of the given options, Brahui is the language of Baluchistan that is linguistically Dravidian.

Sources

1. [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 13: Cultural Setting > Language as a Determinant of Cultural Region > p. 45
2. [2] https://ccat.sas.upenn.edu/~haroldfs/sars238/encybrit.html
3. [3] https://www.britannica.com/topic/Dravidian-languages/Nonliterary-languages