display Flexible Fields from options

According to ACF Docs on Get values from an options page.

You should use ‘option’ not ‘options’ as the second parameter to the have_rows() function.

<?php if( have_rows('repeater', 'option') ): ?>

    <ul>

    <?php while( have_rows('repeater', 'option') ): the_row(); ?>

        <li><?php the_sub_field('title'); ?></li>

    <?php endwhile; ?>

    </ul>

<?php endif; ?>