Which of the following statements is true regarding indexes and averages?

An index compares current stock prices with the top stock in the market while an average is the average of certain stock prices.

An index compares current stock prices with those in a specified base period while an average is the average of certain stock prices.

An index only lists public companies while an average considers all companies.

An index is the average of certain stock prices while an average is simply the average stock price of all publicly traded companies.

An index is a price$-$weighted median while an average is a price$-$weighted average.