The correct answer is: C. It is not possible to calculate the net profit in advance.
A total cost (+) contract is a type of contract in which the contractor is paid for the total cost of the project, plus a fee. This type of contract is generally used in cases where it is difficult to estimate the cost of the project in advance. The fee is intended to cover the contractor’s profit and overhead.
Option A is incorrect because it is not always possible to estimate the cost of a project easily. For example, if the project is complex or if there are a lot of unknowns, it may be difficult to estimate the cost accurately.
Option B is incorrect because the contractor does not necessarily want to earn a certain amount of profit. The contractor may be more interested in getting the project done on time and within budget.
Option D is incorrect because total cost (+) contracts are generally used in cases where it is not possible to calculate the net profit in advance.