Final answer:
A lump sum contract carries the least risk to the contractor as it entails a set price for project completion, making cost management risks predictable and contained compared to other contract types.
Step-by-step explanation:
The contract type that has the least risk to the contractor is a lump sum contract. In a lump sum or fixed price contract, the contractor agrees to complete the project for a predetermined, set price. This means that if they are able to control costs effectively, any savings would increase their profit margin. Conversely, if the project runs over budget, the contractor absorbs those extra costs. This risk is more manageable and predictable compared to other contract types.
In contrast, a cost plus fixed fee contract would involve reimbursement for actual costs plus a fixed fee, which could mean more risk depending on how the costs are managed. A unit price contract typically involves payment based on the quantity of work completed, thus the total cost and risk can vary considerably. The 'Other' category would need explicit definition, but generally would include hybrids or less common contractual agreements which could carry variable levels of risk.
Answer: a. Lump sum