Opt-in" organ donation programs, where adults can choose to enroll in the program, have approximately 15% participation rates; "opt-out" organ donation programs, in which adults are enrolled by default and can choose to decline participation in the program, have approximately 90% participation rates. What best explains this difference? Opt-out programs make participation more available than opt-in programs do. People are averse to losing their organs. Countries with opt-out programs have more caring and generous populations than countries with opt-in programs do. Opt-out framing makes organ donation seem normal, opt-in framing makes it seem like a special act