Question

If no vertical line intersects the graph of a relation in more than one point, then the relation is a function.

Answer 1

If I'm understanding this correctly you mean:
If a vertical line does not connect to more than one point in a relation then that relation is a function.
Then your answer is A-True.
That is called the vertical line test. The vertical line cannot touch more than one point at the same time if it is a function. If it does touch then it is not a function.