I believe the answer is A. X-Coordinate
If I understand what you are asking, you can use the median as an average since it is not affected by the mean ( median is a measure of center). Since a mean is affected by outliers, it might lower the score if there are very low outliers. But note that if there are outliers way <em>greater </em>it can increase the average. You can use the Inter Quartile Range if shown on a box plot ( measure of variability).
The additive identity property states that for every number a, you have

You're showing this property when you write

2.9411764706
but if they're telling you to round, then round (: