If a Graph Structured Stack contains {1,2,3,4} {1,5,3,4} {1,6,7,4} and {8,9,7,4}, what would be the source and sink vertices of the DAC?

If a Graph Structured Stack contains {1,2,3,4} {1,5,3,4} {1,6,7,4} and

1.	If a Graph Structured Stack contains {1,2,3,4} {1,5,3,4} {1,6,7,4} and {8,9,7,4}, what would be the source and sink vertices of the DAC?
A.	Source – 1, 8 Sink – 7,4
B.	Source – 1 Sink – 8,4
C.	Source - 1, 8 Sink - 4
D.	None of the Mentioned
Answer» D. None of the Mentioned