help with arduino ethernet shield html error/ programing

I am trying to make a web page with html and host/ access it with a arduino nano with the ethernet module on top. So far it is working and i can access the web page. the problem i am haveing is when i try to add a radio button with html. i can write text in titles and in the body but when i try to add the client.println("

LED on/off:

"); it wont work and i get the error. inconsistent user-defined literal suffixes 'radio' and 'LED' in string literal.

that’s because you are writing quotes within your string

The syntax analyzer sees 3 strings in your code (highlighted in color)
client.println("

LED on/off:

");

leaving radio and LED hanging around in a weird way and so the compiler tells you it does not understand what you mean as radio and LED are undefined.

client.println("

LED on/off: <input type=radio name=LED />

");

You can’t do that this way, you need to ‘escape’ the character to let the compiler know it’s not the end of the string.

client.println("

LED on/off: <input type=radio name=LED />

");

Have a look at escape sequences to understand how to use this