To decide whether any project is economically feasible or not, the profit from selling the product needs to be greater than the cost of actually producing or making the product.
In the given question, our project is mining.
The total costs for the project = A + B + C + D + E
The total profit for the project = F
Therefore, to verify that the project is economically feasible, the profit (F) needs to be greater that the cost (A + B + C + D + E)
Based on the above, the best choice would be:
a. by confirming that F is greater than A + B + C + D + E