The project to build an art museum for the city is in the planning stages. The project manager has determined that the installation of the marble water feature should be outsourced because his company does not have the necessary expertise. The vendor proposals specify different contract types: cost-plus-fixed-fee, fixed-price, cost-plus-incentive-fee, and time and materials. Which of the proposals present the least probability of loss for the buyer?

a. Proposals that use cost-plus-fixed-fee

b. Proposals that use time and materials

c. Proposals that use cost-plus-incentive-fee

d. Proposals that use fixed-price