Mutually exclusive WPF checkboxes

MainWindow.xaml

<Window x:Class="MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <CheckBox IsChecked="{Binding A}">
        <i:Interaction.Behaviors>
            <local:UncheckOnSignalBehavior Signal="{Binding None}" />
        </i:Interaction.Behaviors>
        Option A
    </CheckBox>
    <CheckBox IsChecked="{Binding B}">
        <i:Interaction.Behaviors>
            <local:UncheckOnSignalBehavior Signal="{Binding None}" />
        </i:Interaction.Behaviors>
        Option B
    </CheckBox>
    <CheckBox IsChecked="{Binding C}">
        <i:Interaction.Behaviors>
            <local:UncheckOnSignalBehavior Signal="{Binding None}" />
        </i:Interaction.Behaviors>
        Option C
    </CheckBox>
    <CheckBox IsChecked="{Binding None}">
        <i:Interaction.Behaviors>
            <local:UncheckOnSignalBehavior Signal="{Binding A}" />
            <local:UncheckOnSignalBehavior Signal="{Binding B}" />
            <local:UncheckOnSignalBehavior Signal="{Binding C}" />
        </i:Interaction.Behaviors>
        None of the above
    </CheckBox>
</Window>

UncheckOnSignalBehavior.cs

using System.Windows;
using System.Windows.Controls.Primitives;
using System.Windows.Interactivity;

public class UncheckOnSignalBehavior : Behavior<ToggleButton>
{
    public static readonly DependencyProperty SignalProperty = DependencyProperty.Register(
        "Signal",
        typeof(bool),
        typeof(UncheckOnSignalBehavior),
        new PropertyMetadata(SignalProperty_PropertyChanged));

    private static void SignalProperty_PropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        ((UncheckOnSignalBehavior)sender).Update();
    }

    public bool Signal
    {
        get { return (bool)GetValue(SignalProperty); }
        set { SetValue(SignalProperty, value); }
    }

    protected override void OnAttached()
    {
        Update();
    }

    private void Update()
    {
        if (AssociatedObject != null && Signal)
        {
            AssociatedObject.IsChecked = false;
        }
    }
}