The multiple correlation coefficient R_{1,23} as compared to any simple correlation coefficients between the distinct variable X_{1} ,X_{2}, and X_{3} is

1. always equal to the product of r_{12}, r_{13} and r_{23}

2. less than any r_{12}, r_{23}, r_{13}

3. not less than any r_{12}, r_{13} and r_{23}

4. always equal to the sum of r_{12}, r_{13} and r_{23}