Answer: a. always true
Step-by-step explanation:
A plane is defined as a line and a point outside this line.
We know that for any set of two points, we can draw a line throug them.
Then if we have "3 points not in the same line" is equivalent to have two points in the same line, and the third point outside of it, then this is the definition of a plane.
Then the correct option is A, always true.
