How do you set dropdown list item text in pageload using .NET C#

I need to be able to set (default option) in my dropdown list  text to read "make a selection" (no value) only when the page first appears!  After a selection is made the drop down list items and values will then be dynamically loaded via a database, C# program etc

protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.Page.IsPostBack)
        {
           what shoulds i put here?
        }
    }

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