How to: Display Option Buttons in a MenuStrip - Windows Forms .NET Framework
Option buttons, also known as radio buttons, are similar to check boxes except that users can select only one at a time. Although by default the ToolStripMenuItem class does not provide option-button behavior, the class does provide check-box behavior that you can customize to implement option-button behavior for menu items in a MenuStrip control.
https://docs.microsoft.com/en-us/dotnet/desktop/winforms/controls/how-to-display-option-buttons-in-a-menustrip-windows-forms?view=netframeworkdesktop-4.8