This block creates a variable with enumerated options. The gui widget is implemented as a combo box or radio button group. When the label is left blank, the option will be used as the label. Set the number of options to "list" to enter a single list of options and labels.
See GUI Hint for how to position the GUI within your window.
This shows the QT GUI Chooser block and how it looks in the output.
Added field for 3.8.1 in July 2020 The "Option 0 (Default)" field has been split into two fields: "Default option" and "Option 0". Whereas the old format forced the default value to be entered as Option 0, the new format allows any of the options to be the default value. Here are what the parameters of the Chooser look like before and after: