Which tool or technique is effective in a project in which the deliverable is not...

According to the PMBOK® Guide and the Standard for Project Management, specifically within the Define Scope process, Product Analysis is the primary tool used when the project deliverable is a tangible product (as opposed to a service or a result).

For projects that have a product as a deliverable, product analysis is a critical technique to translate high-level descriptions into meaningful deliverables. It includes activities such as:

Product breakdown

Systems analysis

Requirements analysis

Systems engineering

Value engineering and value analysis

The other options are incorrect based on the following PMI definitions:

Inspection: This is a tool used in Validate Scope and Control Quality to determine if work and deliverables meet requirements and product acceptance criteria.

Variance Analysis: This is a technique used in Monitor and Control Project Work and Control Scope to determine the cause and degree of difference between the baseline and actual performance.

Decomposition: This is a technique used in Create WBS and Define Activities to divide and subdivide the project scope and project deliverables into smaller, more manageable parts.

As per the PMI Lexicon of Project Management Terms, when the focus is on defining the physical characteristics or functions of a tangible item, Product Analysis is the specified technique.