The correct answer is B. Casey's family owns a store that sells bikes.
Step-by-step explanation:
A discussion is considered as biased when the information included is not impartial or objective but based on personal judgments, prejudices or even interests this implies one or more participants that are part of a discussion are influenced aim at supporting only one side unfairly. In the case of the excerpt presented two participants (Casey and Alex) discuss the use of bicycles vs. the use of automobiles, Casey keeps supporting the idea of using only bicycles, while Alex discusses the idea not everyone can use bicycles. Additionally, Casey might seem to have a more radical perspective as she does not consider only possibilities but only the use of bicycle which suggest she is being biased, moreover as she only supports the use of bicycle the statement that could be the strongest cause of bias in the discussion is "Casey's family owns a store that sells bikes" as this would explain the reason why Cassey is unfairly supporting only one side and being biased.