What is the reimbursement methodology that pays a vendor a pre-determined amount per unit?

The reimbursement methodology described is one in which a vendor is paid a pre-determined amount per unit delivered or completed. This aligns with the characteristics of a Time and Materials contract, where the contractor is reimbursed based on the actual costs of labor and materials used, typically with an established hourly rate for labor, plus the cost of materials.

In contrast, other options describe different approaches. Cost-Reimbursement contracts involve reimbursing the contractor for allowable expenses up to a set limit, therefore they do not align with the concept of a fixed per unit payment. Fixed Price contracts entail a single fixed sum for the entire project regardless of incurred costs, thus not paying per unit. Meanwhile, Performance-Based contracts link payment to the achievement of certain results or performance metrics rather than a straightforward per-unit basis. Therefore, the description provided indicates that the correct methodology is indeed Time and Materials.