The answer is below.
Work Step by Step
a) By asking people who are flying international flights only, you are more likely to find people who enjoy traveling abroad. b) Some people would prefer other countries, such as Spain, to either France or Italy. Thus, asking them which of these two options they would prefer is limiting them to two choices when they may prefer neither of the options. c) People who took a French class are more likely to want to travel to France. Thus, this interviewing method is biased.