Although it is possible to obtain a sample with characteristics that are very different from the population through random sampling, it is more likely that a nonrepresentative sample is the result of __

Selection bias

Explanation:Selection bias refers to selecting individuals in a way that a proper randomisation is not achieved which makes the result not representative of the whole population. This is also called selection effect.This usually occurs when a researcher chooses only participants that will support the idea he has in mind about the variable of interest that they are researching. For example if someone is researching the effect of healthy food on particular population but instead of selecting participants randomly, a researcher goes to a health food market ,vegetable places and gyms. Then a researcher ends up concluding that healthy eating is crucial within this population.

This is wrong because a researcher only chose places that were convenient to this research.

even though you have attached neither the chart nor the generalizations, i have located them online. the right answer is d, since they are asking you about a generalization. you can only infer from the chart that between 2008 and 2009 the number of employed workers decreased significantly (from over 115 millions to 107 millions approximately), which signals some type of economic crisis.