Lecture 5 (Geometry) Postulates and Definitions Concerning Congruence

In an axiomatic system, what role do the postulates play?

1. A.They are the undefined starting words of the system.
2. B.They are the starting assumptions taken to be true.
3. C.They are the implications that must be proven from theorems.
4. D.They are optional remarks that clarify the definitions.