Which output of Project Cost Management consists of quantitative assessments of the probable costs required...

According to the PMBOK® Guide (Project Management Body of Knowledge), specifically within the Project Cost Management knowledge area and the Estimate Costs process:

Activity Cost Estimates (Option A): This is the primary output of the Estimate Costs process. They are defined as quantitative assessments of the probable costs required to complete project work. These estimates can be presented in summary form or in detail and include all resources that will be charged to the project (e.g., direct labor, materials, equipment, services, facilities, and special categories such as inflation allowance or contingency costs).

Earned Value Management (Option B): This is a methodology or a tool and technique used in the Control Costs process. It integrates scope, schedule, and resources to measure project performance and progress. It is not an output consisting of initial cost assessments.

Cost Management Plan (Option C): This is an output of the Plan Cost Management process. It is a component of the project management plan that describes how the project costs will be planned, structured, and controlled. It sets the " rules " for estimation but does not contain the actual quantitative estimates for activities.

Cost Baseline (Option D): This is the approved version of the time-phased project budget. While it is built using the activity cost estimates, it represents the formal benchmark for measuring performance and includes contingency reserves, but it is a higher-level aggregation rather than the raw quantitative assessment of individual activity costs.

In the PMI framework, Activity Cost Estimates provide the granular data necessary to eventually roll up into the work package estimates, which then form the basis for the Cost Baseline.