About failsafe jQuery code

About failsafe jQuery code

I am confusing with following code. Are they do the same thing and all
failsafe code? In my guess the second and third are not failsafe code. Am
I right?
jQuery(function ($) {
});
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$(function ($) {
});
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$(document).ready(function ($) {
});
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jQuery(document).ready(function ($) {
});