Two variables are plotted on a graph and a relationship is derived, this is an example of?

The answer is B.  Scatter Diagram. 

B. Scatter diagram

Thanks.................

My oppinion is that the right answer is:

B. Scatter Diagram

Scatter diagram is the apt answer since two variables are plotted for finding the relationship

Scatter diagram, thanks for your invitation.

 Deriving Relationship between variables on a graph is an example of Scatter Plot

I leave the answer to experts and specialists in this area this is not my specialty field

B.  Scatter Diagram is the most suitable answer.

You have an answer already i.e 

B.  Scatter Diagram