Adds the appropriate column class to the given options applicable. The available columns are 'xs', 'sm', 'md',
'lg' for extra small, small, medium, and large to be used for the appropriate screen sizes. It is also possible
to prevent your columns from stacking on smaller devices by combining a small column with a larger column:
$htmlOptions = array(
'xs' => 12,
'md' => 8,
)
Both classes will be applied.