A poll asked $870$ adults how many books they read last year. The results were:

Find the mean, median, and mode of the data, if possible. If any measure cannot be found or does not represent the center of the data, explain why.

• A. Mean: "$3\text{–}9$ books" groupMedian: "$3\text{–}9$ books" groupMode: "$3\text{–}9$ books" group
• B. Mean: cannot be found (data is grouped)Median: cannot be found (data is grouped)Mode: "$3\text{–}9$ books" group
• C. Mean: cannot be found (data is grouped)Median: "$3\text{–}9$ books" groupMode: "did not read any books" group
• D. Mean: cannot be found (data is grouped)Median: "$3\text{–}9$ books" groupMode: "$3\text{–}9$ books" group

Answer: (D)