The Vanguard 500 Index Fund tracks the performance of the S&P 500. To do so, the fund buys shares in each S&P 500 company ______. A) by purchasing an equal dollar amount of shares of each stock in the S&P 500 B) by purchasing an equal number of shares of each stock in the S&P 500 C) in proportion to the price weight of the stock in the S&P 500 D) in proportion to the market value weight of the firm's equity in the S&P 500