Assign a priority order $(1-4$; $1$ is greatest priority$)$ to the following four groups for the purposes of determining $R$ and $S$ configurations at a stereocenter.

$\backslash$table$[[,$Group $"$A$",$Group $"$B$",$Group $"$C$",$Group $"$D$"],[,-C{H}_3,-OH,-C{H}_{2}C{H}_3,-C{H}_{2}OH$