Answer: (b)

Explanation:
The term kshetra-patni ("mistress of the field") is found in the Vedic literary tradition and is associated particularly with the Atharvaveda, where agricultural fertility and household prosperity are invoked through hymns addressed to deities linked with land and production. In this context, kshetra-patni refers to a divine or symbolic feminine force associated with the fertility and protection of agricultural fields.

While the Rigveda also contains many hymns related to nature and deities, the specific usage of terms connected with settled agricultural life, fertility rituals, and domestic prosperity is more characteristic of the Atharvaveda. The Ashtadhyayi is a grammatical text, and the Arthashastra deals with administration and political economy, not Vedic ritual terminology of this kind. Therefore, the correct source of the term is the Atharvaveda.