A circuit is replaced by its Thevenin's equivalent to finding current through a certain branch. If VTH = 10 V and RTH = 20 Ω, the current through the branch:
1
will always be equal to or less than 0.5 A
2
will always be 0.5 A
3
will always be less than 0.5 A
4
may be 0.5 A or more or less