You Have Collected the Data for a Time-Cost CPM Scheduling

Multiple Choice

You have collected the data for a time-cost CPM scheduling model analysis. The time is in days and the project "direct costs" are given here. The indirect costs for the project are determined on a daily duration basis. If the project lasts 16 days, the total indirect costs are $400; 15 days, they will be $250; 14 days, they will be $200; and 13 days, they will be $100.
At what day do we achieve the lowest total project cost (i.e., direct plus indirect costs) ?

A) 16 days
B) 15 days
C) 14 days
D) 13 days
E) 12 days