Solve the question on the picture with linear optimalization in Excel?A project is composed of $7$ activities labeled as A$,$ B$,$ C$,$ D$,$ E$,$ F$,$ and G$.$ The durations in

days and precedence constraints of the activities are given in the following figure.

For example, activity E$,$ that takes $4$ days, can only start after activities $B$ and $C$ have been

finished.

a$.(3)$ Solve a linear optimization model to determine the earliest project finish time.

b$.(1)$ Activities D and E now use the same resource and cannot be executed at the same

time. What is the optimal schedule and finish time? Give a convincing argument.

c$.(1)$ Integrate part b$.$ in one $($integer$)$ linear optimization model to find the optimal

schedule and finish time. $($Hint: Use a binary variable indicating which one goes first$).$