<select class="form-select form-control-sm" id="cveCar" name="cveCar">
    <option value="default">Selecciona</option>
    {% if carreras is defined %}
        {% for c in carreras %}
            <option value="{{c.ideLicTit}}">{{c.nomLic}}</option>
        {% endfor %}
    {% endif %}
</select>