Assertion-Reason: Grounded theory
Assertion (A): Theoretical sampling ultimately leads to theoretical saturation in grounded theory. Reason (R): Grounded theory requires checking emerging theory against reality by sampling incidents that may further its development until no new categories can be identified.

Correct option is A

Theoretical sampling is the iterative process of collecting data guided by emerging theory, continuing until no new properties or categories emerge — this is precisely theoretical saturation. R accurately explains why/how A occurs.
Information Booster:
1. Grounded theory was developed by Glaser and Strauss.
2. Theoretical sampling differs from random/convenience sampling — it's driven by the developing theory.
3. Saturation is a signal to stop data collection.
4. Core grounded theory techniques: open coding, axial coding, selective coding.