Matrix-field with a category-field to output category-title on single entry page
Nevermind, the problem is solved.

I just need to loop over the categories.

{% extends "matrix/default" %}
{% block blockContent %}
&lt;div class="row"&gt;
    &lt;div class="col flexcntr"&gt;
        {% for merk in block.merkNaam %}
            {{ merk.title }}
        {% endfor %} #}
    &lt;/div&gt;  
&lt;/div&gt;
{% endblock %}