To show dependencies in a schedule, the project manager should use a network diagramming technique- specifically, the Precedence Diagramming Method (PDM). PDM represents activities (nodes) and connects them with relationships (arrows/links) to show task ordering and dependency logic. CompTIA Project+ explicitly includes analyzing and using a project network diagram as a tool, and it also emphasizes understanding dependencies and successor/predecessor relationships (finish-to-start, start-to-start, etc.), which are exactly what PDM models.
The other options don't match the requirement. Waterfall is a life-cycle methodology, not a dependency diagramming tool. Simulation is typically used for quantitative analysis (e.g., Monte Carlo) rather than directly drawing dependencies. Cost ratio analysis is financial decision support, not schedule dependency mapping.
Therefore, to build a schedule that clearly communicates task order, constraint logic, and critical sequencing, the PM should use precedence diagramming (a form of project network diagram) to visualize and manage dependencies during initiation and early planning.