Which of the Following Best Explains 'Unit Rate/charter Contracts

Multiple Choice

Which of the following best explains 'unit rate/charter contracts'? 

A)  Contractor agrees to work based upon compensation of all actual costs incurred plus profit margin. 
B)  Contractor agrees to work based upon compensation of all actual cost. 
C)  Contractor agrees to work based on projected costs only. 
D)  Contractor agree to work based on outcome of further negotiations.