Rationale for Correct Answer (D):

The Terraform Registry provides documentation for published modules, including:

Required inputs (variables you must supply).

Optional inputs with defaults (so you know what you can override).

Outputs (what values the module returns for use elsewhere).

Therefore, the correct answer is all of the above.

Analysis of Incorrect Options:

A. Required inputs only: Incomplete.

B. Outputs only: Incomplete.

C. Optional inputs only: Incomplete.

D. All of the above: Correct because the Registry provides all relevant documentation.

Key Concept:

Terraform Registry modules include inputs, outputs, and usage details, enabling reusability and modular design.