Consider the following optimal solution to the maximal flow problem represented by the following Excel spreadsheet.

Units					Upper				Net	Supply/
Of Flow	From		To		Bound		Nodes		Flow	Demand
4	1	A	2	B	4		1	A	?	?
8	1	A	3	C	8		2	B	?	?
4	2	B	4	D	6		3	C	?	?
0	2	B	5	E	2		4	D	?	?
4	3	C	4	D	4		5	E	?	?
4	3	C	5	E	5
8	4	D	5	E	9
11	5	E	1	A	999

What is the supply/demand value for node 3?

Select one:

a. 1

b. -1

c. 0

d. Binary