A factory makes a product that has a manufacturing process consisting of tasks $A,$dots,$J$ that must be completed in an order that obeys a set of precedence

requirements. The following table reports the performance time in minutes$/$unit and the preceding task$($s$)$ for tasks A$,...,$ J$.$

The precedence network is:

The line will operate for $420$ minutes per shift. The desired shift output is at least $20$ units.

The configuration Station $1($ABC$)$; Station $2($DEF$)$; Station $3($GH$)$; Station $4($IJ$)$

The configuration Station $1($ABF$)$; Station $2($CD$)$; Station $3($EGH$)$; Station $4($IJ$)$

The configuration Station $1($AFG$)$; Station $2($HIJ$)$; Station $3($BC$)$; Station $4($DE$)$