Final answer:
Claim A regarding teenagers' brand preferences necessitates the most representative sample. This helps ensure that the findings apply to the larger teenage demographic, capturing a true reflection of their brand choices.
Step-by-step explanation:
Having a representative sample is crucial for making valid generalized claims about a population. Among the claims provided, Claim A would require the most representative sample because it involves a specific age group and a preference between two options. To validate this claim, it's essential to have a sample that accurately reflects the demographics of all teenagers, including their various backgrounds and interests. This ensures that the sample's preferences are indicative of the larger population's preferences. This claim is based on the preference of teenagers, and in order to accurately represent the entire population of teenagers, a representative sample must be used.