Concept:The most popular value in any data set is simply the value that occurs most frequently.
Explanation:The question asks which statistical measure identifies the most common dress or shoe size among buyers.
The range only gives the difference between the smallest and largest sizes, so it does not show popularity.
The mean gives the average size, but this can be affected by very large or very small sizes.
The median gives the middle size when all sizes are arranged in order, not the most frequent one.
The mode is the size that appears most often in the collected data.
Since “most popular” means the size with the highest frequency, the mode must be used.
Answer:C. mode