A simple menu that rejects invalid options

@ECHO off

cls

:start

ECHO DEFAULTS TO D WHICH WILL FAIL.

ECHO A. Case insensitive

ECHO b. second option

set choice=D

set /p choice=Type the letter

if not '%choice%'=='' set choice=%choice:~0,1%

REM the next line is case insensitive

if /I '%choice%'=='A' goto optiona

if '%choice%'=='b' goto optionb

ECHO "%choice%" is not valid, try again

ECHO.

goto start

:optiona

ECHO You typed A

goto end

:optionb

ECHO You typed B

goto end

:end

GOTO START