My favorite moments at this week’s GOP debate were when my wife, CNBC senior personal finance correspondent Sharon Epperson, challenged the candidates to confront two of the biggest issues facing America: student loans and retirement. Nobody wants to talk about retirement in part because it’s hard to face up to the idea of getting old, and many folks don’t want to talk about student loans because we’re filled with guilt about failing our young. Retirement and student loans may not be sexy subjects, but they are just the kind of important issues candidates need to grapple with during an election year. “This country has over $100 billion in student loan defaults–that’s billion with a b,” Sharon said during the debates, before posing her question. “What will you do to make sure that students, their families, taxpayers, won’t feel the economic impact of this burden for generations?” Here are the videos of the questions Sharon posed to the GOP candidates.