Which parties are involved in a traditional contract delivery system?

In a traditional contract delivery system, the primary parties involved typically include the owner, contractor, and the architect. The owner engages the architect to design the project, and then the contractor is hired to execute the construction according to the architect's plans.

The correct answer, which identifies the owner, contractor, and engineer, reflects the essential roles in this system. The owner initiates the project, the contractor is responsible for the construction, and the engineer may be involved in ensuring that the project adheres to engineering standards and specifications, particularly in technical and complex projects.

The other options do involve relevant parties but do not accurately represent the core relationships in a traditional contract delivery system. For instance, the role of the foreman or supplier is more operational or logistical and is not typically considered a primary party involved in the contract itself. Each party listed in the incorrect options serving an essential role is still not central to the contractual relationship defined in this context.