You have $20,000. You plan on purchasing a house in one year, but you will need to have $22,500 for the down payment. Which of the following is a good investment opportunity to ensure you have the money necessary to make your down payment in a year?

1. A portfolio with an expected return of $30,000 and a standard deviation of 15%.

2. A portfolio with an expected return of $24,000 and a standard deviation of 10%.

3. A portfolio with an expected return of $27,000 and a standard deviation of 20%.

4. All of these options would be a good investment.

Why is #1 correct?