Option-1 states that both statements are individually true and Statement II is the correct explanation of Statement I. Let`s analyze each statement to understand why this option is the correct answer.

Statement I asserts that the early Aiyans, who were primarily pastoral, did not develop a political structure comparable to a State in any ancient or modern sense. This means that the Aiyans did not have a centralized governing system with defined territories and administrative hierarchies like a State. Instead, they had a more tribal and decentralized organization.

Statement II states that kingship was equivalent to tribal chiefship among the Aiyans. The term "Rctjan" was used to refer to a tribal chief who primarily served as a military leader and ruled over his people, rather than a specific geographical area.

Statement II is a correct explanation of Statement I because it provides an understanding of why the Aiyans did not have a political structure comparable to a State. The usage of the term "Rctjan" highlights that the Aiyans had a system where leadership was based on military prowess, rather than territorial control.

Therefore, Option-1 is the correct answer as both statements are individually true, and Statement II provides the correct explanation for Statement I.