In most U. S. states, before people can vote, they have to opt-in by actively registering to vote. But in some states, citizens are automatically registered to vote when they get a driver's license, but can opt-out if they so choose.
Based on the findings described in the text, we should expect all of the following to be true EXCEPT that:

a) people in opt-out states will be unlikely to opt-out.
b) people will be as likely to be registered to vote in opt-in states as opt-out states.
c) voter participation will be higher in opt-out states.
d) in opt-in states, the number of people who are in favor of voting is likely to be higher than participation.