The correct answer is D. total cost concept.
The total cost concept is a method of measuring the cost of a project by adding up all the costs associated with the project, including both direct and indirect costs. However, this method cannot be used to measure the social cost benefit of a project because it does not take into account the social benefits of the project.
The social benefits of a project are the benefits that accrue to society as a whole as a result of the project. These benefits can include things like improved air quality, reduced traffic congestion, and increased employment opportunities. These benefits are not always easy to quantify, but they are an important part of the overall cost-benefit analysis of a project.
The other options, A, B, and C, are all methods that can be used to measure the social cost benefit of a project.
The capital output ratio is a measure of the efficiency with which a project uses capital. It is calculated by dividing the total output of the project by the total capital investment in the project. A high capital output ratio indicates that the project is using capital efficiently, while a low capital output ratio indicates that the project is not using capital efficiently.
The value added method is a method of measuring the economic value of a project. It is calculated by subtracting the value of the inputs to the project from the value of the outputs of the project. The value added method can be used to measure the social benefits of a project, as well as the social costs of a project.
Saving in foreign exchange is a measure of the amount of foreign exchange that a project saves. This is important because foreign exchange is a scarce resource, and projects that save foreign exchange can benefit the economy as a whole.
In conclusion, the total cost concept is a method of measuring the cost of a project, but it does not take into account the social benefits of the project. The other options, A, B, and C, are all methods that can be used to measure the social cost benefit of a project.