RadioButtonList answerButtons = new RadioButtonList();
answerButtons.RepeatDirection = RepeatDirection.Horizontal;
ListItem[] answers = new ListItem[]
    {
        new ListItem() { Text = "Negative", Value = "1" },
        new ListItem() { Text = "Positive", Value = "2" },
        new ListItem() { Text = "None", Value = "3" }
    };
answerButtons.Items.AddRange(answers);
<some_control>.Controls.Add(answerButtons);
// answerButtons.ClientIDMode = <?>