$10\mathrm{.}7-2.$ Reconsider the minimum cost flow problem formulated in Prob. $10\mathrm{.}6-2.$

$($a$)$ Obtain an initial BF solution by solving the feasible spanning

tree with basic arcs A $!$ B$,$ A $!$ C$,$ A $!$ F$,$ B $!$ D$,$and

E $!$ F$,$where two of the nonbasic arcs $($E $!$ C and

F $!$ D$)$ are reverse arcs.

D$,$I $($b$)$ Use the network simplex method yourself $($you may use the

interactive procedure in your IOR Tutorial$)$ to solve this problem.