For each of the following, state whether the events created are mutually exclusive and collectively exhaustive.
a. Registered voters in the United States were asked whether they are registered as Republicans or Democrats.
b. Each respondent was classified by the type of car he or she drives: sedan, SUV, American, European, Asian, or none.
c. People were asked, "Do you currently live in (i) an apartment or (ii) a house?"
d. A product was classified as defective or not defective.