Dropdown selected value is not showing after selection flask?

How to use HTML <select> dropdown list which is prepopulated from flask - render_template.

Here is the <select> dropdown list which is prepopulated from flask-jinja2.

<div>
               <select class="test-default" id="testTime">
                {% for option in options %}
                <option value={{ option }}>{{ option }}</option>
                {% endfor %}
            </select>
                </div>

Script in test.html,

function fetch_test_data(){
    let test = $("#testTime").val();
    axios({ 
        method:"get",
        url:"/test",
        params: {
            test
        }
    }).then(function (response) {
        $(document.body).html(response.data)
    }); 
}

And test.py file - with app route and options for dropdown.

        @app.route('/test', methods=["GET"])
        @login_required
        def transactions_view():
            options = ["0","7","14","30"]

            return render_template("test.html", options=options)

In the above case how to use selected attribute to display the selected value.

when a value is selected, The correct value is returned to the flask and rendered back. But dropdown visualization/list shows the first value instead of selected value?

What I have tried:
I'm able to get dropdownselect for defined dropdown.

defined-dropdown - for reference

<div>
        <select class="test-default" id="testTime">
        <option value=0>today</option>
        <option value=7>week</option>
        <option value=14>fortnight</option>
        <option value=30>month</option>
        </select>
        </div>

        {{ time }}

I'm able to use the above dropdown to this:

<div>
            <select class="test-default" id="testTime">
            <option value=0 {% if time == 0 %} selected="selected" {% endif %}>today</option>
            <option value=7 {% if time == 7 %} selected="selected" {% endif %}>week</option>
            <option value=14 {% if time == 14 %} selected="selected" {% endif %}>fortnight</option>
            <option value=30 {% if time == 30 %} selected="selected" {% endif %}>month</option>
            </select>
        </div>

Where {{ time }} is returned from test.py

    @app.route('/test', methods=["GET"])
    @login_required
    def transactions_view():
        time = (request.args.get("test"))
        return render_template("test.html", time=time)