Ruth is working on procurement management process. She was involved in plan procurement management. She is working on the cost-reimbursable contract. In this type of contract, the seller is reimbursed with all the allowable costs to perform the contract work and receive a fixed-fees payment calculated as a percentage of the initial estimated project costs. The fees which is used in cost-plus contracts to encourage the seller to increase the performance of the work is known as?

A. Fixed fees.

B. Economic price adjustment fees.

C. Incentive fees.

D. Award fees.