Solution
As per the passage, Panini primarily discussed the impact of language on derivative words.
According to the paragraph, "Panini discusses, in a few sutras scattered over his works, the influence of the concept of language in various spheres of suffixes, primary and secondary derivatives and compounds." The passage specifically highlights Panini's focus on how language influences derivatives, compounds, and the formation of words through suffixes.
While the passage mentions terms like 'jati', 'kriya', 'guna' and 'dravya', these are presented as grammatical concepts that poetics borrowed from grammar, rather than being Panini's primary focus. Similarly, philosophical issues and critical questions are discussed in relation to Sanskrit literary tradition broadly, not specifically as Panini's main concern.
Hence, the correct answer is Option 2: Impact of language on derivative words.