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.

When creating a security market index, the target market:
Option A:determines the investment universe.
Option B:is usually a broadly defined asset class.
Option C:determines the number of securities to be included in the index.

Answer: A