This question already has an answer here:
https://math.stackexchange.com/questions/1034067/prove-language-is-not-regular-with-pumping-lemma?noredirect=1 was recently closed, and the banner says, inaccurately:
put on hold as off-topic by Micah, hardmath, daw, Rafflesia arnoldii, MJD
The first four of those five users did vote to put it on hold as off-topic. But MJD did not. MJD voted to close because the question is a duplicate of How do we choose a good string for the pumping lemma?.
I wish the banner accurately described the state of affairs.