A pipe laying project is being executed on a one$-$kilometer line. If the activities are excavation, pipe laying and backfill, prepare the network diagram and Gantt chart for the following sequence of activities.

$\backslash$table$[[,$ACTTVTIES,Duration,Prerequisities$],[$A$,$Excavate $1^{s1}250$ meters of trench,$10,$None$],[B,$Lay $1^{s1}250$ meters of pipe,$6,$A$],[C,$Backfill $1^{3t}250$ meters of pipe,$4,$B$],[$D$,$Excavate $2^{nd}250$ meters of trench,$1/4,$A$],[E,$Lay $2^{nd}25$ meters of pipe,$6,D$