Explanation
A dependency is a relationship or a condition that affects the completion or the quality of a task or an activity.
A dependency can be internal or external, mandatory or discretionary, or positive or negative. In this case, the inspector's signoff on the initial deliverables is a dependency because it is a condition that must be met before the task can be completed. The inspector's signoff is an external and mandatory dependency, as it involves an outside party and it is required by the project scope or contract. A dependency is not the same as an assumption (A), which is a factor that is considered to be true without proof, a milestone, which is a significant point or event in the project, or a constraint (D), which is a factor that limits the options or performance of the project. References:
What is a Dependency in Project Management? - Wrike, paragraph 1
Project Dependencies: Types, Examples, and Tips for Project Managers, paragraph 1 CBAP Certification Study Guide v3.0, Chapter 4: Requirements Life Cycle Management, Section 4.3:
Trace Requirements, page 4-10
[A Guide to the Business Analysis Body of Knowledge (BABOK Guide)], version 3, page 402, section
10.31.3.1