A new storm drainage system must be constructed right away to reduce periodic flooding that occurs in

a city that is in a valley. Five mutually exclusive designs have been proposed, and their present

worth $($in thousands of dollars$)$ of costs and benefits are the following.

a$.$ Which system has the greatest $B-C$ ratio?

b$.$ Which system has the largest incremental B$-$C ratio $($based on differences between alternatives$)?$

c$.$ Which system should be chosen?

a$.$ System has the greatest $B-C$ ratio, which is $($Round to two decimal places.$)$

b$.$ System has the largest incremental B$-$C$,$ which is $($Round to two decimal places.$)$

c$.$ System $$ should be chosen.