13. Which statement best explains root-n convergence? options are: a. If the number of observations (n) doubles, the standard errors will increase by square root of 2 b.The variance increases with the square root of the sample size; the standard errors can be expected to increase proportionally with the sample size c.standard errors can be expected to increase proportionally with the square root of the sample size d.standard errors can be expected to shrink at the same rate as the inverse of the square root of the sample size. Provide and explain the