find optimal distribution from source to destination using Network simplex algorithm. using the following data ; Demand $=(5,3,8,17)$ Supply $=(10$; $15$; $8)$ source $($S$)$ and Destination $($D$)$ are as follows; $($S$1,$D$1)=10,($S$1,$D$2)=10,($S$1,$D$3)=6,($S$1,$D$4)=15,($S$2,$D$1)=5,($S$2,$D$2)=15,($S$2,$D$3)=10,($S$2,$D$4)=12,($S$3,$D$1)=11,($S$3,$D$2)=8,($S$3,$D$3)=7,($S$3,$D$4)=21$