Given a text T, and several options, according to the question posed in the text T to choose the most appropriate option from the options as the answer, please directly output the most appropriate option, do not need to output the explanation.

Which of the following groups best illustrates a population?
Option A:The 500 companies in the S&P 500 Index
Option B:The NYSE-listed stocks in the Dow Jones Industrial Average
Option C:The Lehman Aggregate Bond Index as a representation of the US bond market

Answer: A