you got 2 ways to achieve this, choose
1. Go to this File: /templates/ja_university_t3/html/com_content/category/blog.php
Find this code and replace it
[PHP]
<?php if (!empty($this->children[$this->category->id])&& $this->maxLevel != 0) : ?>
<div class=”cat-children”>
<?php if ($this->params->get(‘show_category_heading_title_text’, 1) == 1) : ?>
<h3> <?php echo JTEXT::_(‘JGLOBAL_SUBCATEGORIES’); ?> </h3>
<?php endif; ?>
<?php echo $this->loadTemplate(‘children’); ?> </div>
<?php endif; ?>
[/PHP]
with
[PHP]
<?php /*?><?php if (!empty($this->children[$this->category->id])&& $this->maxLevel != 0) : ?>
<div class=”cat-children”>
<?php if ($this->params->get(‘show_category_heading_title_text’, 1) == 1) : ?>
<h3> <?php echo JTEXT::_(‘JGLOBAL_SUBCATEGORIES’); ?> </h3>
<?php endif; ?>
<?php echo $this->loadTemplate(‘children’); ?> </div>
<?php endif; ?><?php */?>
[/PHP]
or
2. From your menu item expand the category options positions on the right side and change the subcategory level to ‘None’