Answer:
Option B)- Median, because there is 1 outlier that affects the center
Step-by-step explanation:
The Outlier is a point that is different from other points. Since 9 is an outlier( its distance from other points in data is large) and when an outlier is present in the data we use the median for finding the best measure of central instead of mean because outlier can affect our analysis.
Option A is incorrect because mean get affected much by outliers.
Option C is not correct because it is used to measure dispersion.
As in First Period outlier is present, So Option D can't be chosen.