Which of the following statements is true about diversification?

1. The benefit from diversification is maximized if the correlation coefficient is zero

2. If the covariance between two securities is negative, then the portfolio's standard deviation can be reduced to zero

3. The variance is the weighted average of the individual securities' variances

4. By diversifying, portfolio risk can be reduced to zero

5. There is no benefit from diversification if the correlation coefficient is 1