Which former president is NOT mentioned among the living former presidents?

The choice identifying George H.W. Bush as the correct answer is accurate because he passed away on November 30, 2018. Therefore, he is not among the living former presidents. In contrast, Bill Clinton, Barack Obama, and Joe Biden are all alive and have served as presidents, making them part of the group of living former presidents. This understanding is crucial as it highlights the importance of current status concerning historical figures and their legacies, as well as the need for awareness when discussing living former political leaders.