Which of the following portfolios is the most diversified?

a)Joshuas investment portfolio is invested in 25 stocks in different industries.

b)Kyles portfolio is invested 50 percent in an S&P 500 stock index and 50 percent in his employers stock.

c)Christinas portfolio is invested 50 percent in a stock mutual fund and 50 percent in a bond mutual fund.

d)Emilys portfolio is only invested in her employers stock.