$optionsB = array(
t('level 1') => drupal_map_assoc(doTasksQuery('level 1')),
t('level 2') => drupal_map_assoc(doTasksQuery('level 2')),
t('level 3') => drupal_map_assoc(doTasksQuery('level 3')),

$optionsB = array();
foreach ( $levels as $level ) {
    $optionsB[ t( $level ) ] = drupal_map_assoc( doTasksQuery( $level ) );
}