Research Conducted by Professors Cass Sunstein and Richard Thaler Show

Research conducted by Professors Cass Sunstein and Richard Thaler show that employees are much more likely to enroll in a savings plan under automatic enrollment than under a default term of non-enrollment because it turns out that very few employees drop out if automatically enrolled. Source: Sunstein,Cass R.and Richard H.Thaler.2003."Libertarian Paternalism Is Not an Oxymoron," University of Chicago Law Review,70:1159-1202.
What does this suggest about getting people to save for their retirement?

A) Planning for one's retirement is complex and emotional and most people deliberately avoid confronting these financial decisions.
B) People are overly pessimistic about their future financial prospects; many fear that the social security scheme may be non-existent by the time they retire.
C) Many people need to be "tricked" into saving because they are unrealistic about their future behavior. They spend money today that they should be saving for retirement, partly because they overestimate their ability to save in the future.
D) One way to get people to save more is to make mandatory contributions to a saving plan part and parcel of employment, and to make opting-out legally impossible.