Final answer:
Based on the provided materials, the closest age group to a mean age of 72 would be 'Ages 65 and older' since it includes the young-old subgroup, which ranges from about sixty-five to seventy-four years old.
Step-by-step explanation:
The Pew Research Center survey from 2009 does not clearly outline a mean age of 72 for any specific group of respondents in the materials referenced. However, considering the options provided, the age group that most closely aligns with a mean age of 72 would be 'Ages 65 and older'. This is supported by the information indicating that this demographical cohort includes subgroups such as the young-old (approximately sixty-five to seventy-four years old).