It is the last option: "if an angle is bisected,
then the two resulting angles will have equal measure".
The form of this syllogism is: A => B; B=> C; then A => C
1) An angle is bisected => the two resulting angles are congruent ;
2) Two resulting angles are congruent => they will have equal measure
Conclusion: Then, An angle is bisected => the two resulting angles will have equal measure