---

private int secretNumber;
private string[] roman = { "", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX", "X" };

private void Form1_Load(object sender, EventArgs e)
{
    secretNumber = new Random().Next(1, 11);
    // Установить ToolTip для каждого RadioButton (rb1..rb10)
    ToolTip tip = new ToolTip();
    tip.SetToolTip(rb1, roman[1]);
    tip.SetToolTip(rb2, roman[2]);
    // ... и так до rb10
}

private void rbNumber_CheckedChanged(object sender, EventArgs e)
{
    RadioButton rb = sender as RadioButton;
    if (rb != null && rb.Checked)
    {
        int chosen = int.Parse(rb.Text);
        if (chosen == secretNumber)
            MessageBox.Show("Правильно!");
        else
            MessageBox.Show($"Неверно! Загаданное число: {secretNumber}");
        secretNumber = new Random().Next(1, 11);
    }
}