Comprehensive and Detailed Explanation From Exact Extract (CSI-aligned, paraphrased)

CSI’s project delivery framework places the owner at the center of the facility life cycle. The owner:

Initiates the project by defining needs and project goals.

Selects the project delivery method and engages the design and construction teams.

Participates in planning, design decisions, funding, and approvals.

During construction, the owner is responsible for payments, change decisions, and acceptance of the work.

After construction and closeout, the owner (often through a facility management group) is responsible for operation, maintenance, and long-term performance of the facility.

CSI repeatedly highlights that only the owner is engaged from the earliest concept through long-term operation and eventual renovation or disposal. All other parties (designers, contractors, manufacturers) participate for limited phases.

Therefore, the party “actively involved and interested in all phases of the project” is clearly:

B. Owners

Why the other options are incorrect:

A. ContractorsContractors typically become formally involved at procurement/bidding and remain through construction and closeout. They usually have no role in early planning (except in some delivery methods like CM-at-Risk or IPD where they join during design) and no long-term responsibility for operations beyond warranty obligations.

C. Architects/engineersThe A/E’s primary involvement is during planning and design, and then construction administration during construction and closeout. After the project is turned over, their involvement often ends unless separately engaged for post-occupancy evaluations or future work. They do not normally manage day-to-day operations and maintenance.

D. Manufacturers/suppliersManufacturers and suppliers participate mainly in product selection, submittals, and furnishing materials and equipment during design-assist and construction phases. They may have continuing obligations for warranties or support, but they are not engaged in every phase of the project’s life cycle as the owner is.

Key CSI-Related References (titles only):

CSI Project Delivery Practice Guide – roles and responsibilities of the owner, design professional, contractor, and others.

CSI Facility Management Practice Guide – owner’s role during operations and the extended facility life cycle.

CSI CDT Study Materials – diagrams and explanations of project participants over the facility life cycle.