A toll road can be built one of two ways. It can be built as one entity and opened at once at an initial cost of $20 M. The annual income would then be $4 M per year, and maintenance costing $6 M would have to be done every 4 years. The second alternative would be to build the road in two parts. The initial part would cost $8 M and the second part would be built after 4 years at a cost of $8 M. The annual income would be $2 M until the second part is open and it would then be $4 M. The maintenance cost of the first part would be $2 M after 4 years and $6 M after 8 years. Considering an 8 year analysis time, which construction option should be chosen? Show all working, and your answer has to be justified. The interest rate is 5%.