Which of the following is NOT an example of a metric?

The most frequent values of a dataset column $($e$.$g$.$ "United States"$)$

The number of files in a managed folder $($e$.$g$.100)$

The accuracy of a machine learning model $($e$.$g$.0\mathrm{.}85)$

Whether or not a column has more than some number of missing values $($e$.$g$.$ OK$)$