Final answer:
Clark was nicknamed 'America's Oldest Living Teenager' and passed away in 2012. He was a renowned television host known for his youthful appearance and for hosting 'American Bandstand.'
Step-by-step explanation:
The man famously nicknamed 'America's Oldest Living Teenager' who passed away in 2012 is Clark. Clark was a television host and media personality well-known for his youthful appearance, which contributed to his enduring nickname. He was perhaps best known for hosting the television program American Bandstand, as well as the annual New Year's Rockin' Eve broadcast from Times Square in New York City. Clark's contributions to American television and music were significant, making him a notable figure in the entertainment industry for decades.