Which level of abstraction describes how data are stored in the database?

Concept

A database is described at three levels of abstraction, and each level answers a different question about the same data. The physical level answers how the data are stored, the logical level answers what data are stored and how those items relate to one another, and the view level answers which part of the data a particular user or application is shown.

Applying it here

The stem asks for the level whose description is about storage itself — the way the data are laid out on the storage device. That is the lowest of the three levels, the physical level: it fixes the file organisation, the layout of records and blocks, the access paths and index structures, and the encoding or compression used on disk.

Cross-check

Test the other names against the same question. A description of what data are held and how they relate is the logical level; a description of the slice shown to one user or application is the view level; and "abstraction level" is the umbrella name of the three-level scheme itself rather than one of its tiers. Only the physical level is defined in terms of storage, so the answer is Physical level.