$10\mathrm{.}7-2.$ 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 $AB,AC,AF,BD,$ and

$EF,$ where two of the nonbasic and

$FD)$ 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.