If you wished to value a corporate project for a firm, what method described below would likely give a decent $($if not perfectly accurate result$)?$

A$)$ Add benefits and deduct costs, discounting each by a rate determined from a model. If the sum is positive, invest, otherwise do not invest.

B$)$ Add benefits and deduct costs. Multiply the sum by the discount rate. If the total is greater than $1,$ invest, otherwise do not invest.

C$)$ Add benefits, divide by total costs. Subtract this figure from the discount rate. If the total is greater than $0,$ invest, otherwise do not invest.

D$)$ Add benefits, divide by total costs. Subtract this figure from the discount rate. If the total is less than $0,$ invest, otherwise do not invest.

E$)$ As investment is inherently risky and certain, there is unfortunately no method to estimate the value of a firm project.