Select the choice that correctly describes three meanings of the area under a normal density curve to the left of a point $x_0$.

$P(X\le x_0)={\int }_{-\infty }^{x_0}f\left(x\right)dx$; the area is the percentile rank of $x_0$; the area is the expected proportion of future observations less than or equal to $x_0$.

$P(X\le x_0)={\int }_{-\infty }^{x_0}f\left(x\right)dx$; the area equals $f\left(x_0\right)$; the area equals the interquartile range.

$P(X\le x_0)={\int }_{-\infty }^{x_0}f\left(x\right)dx$; the area equals the variance of $X$; the area equals the probability density at the mean.

$P(X\le x_0)={\int }_{-\infty }^{x_0}f\left(x\right)dx$; the area equals the sample median; the area equals the mode of the sample.