What is the criteria for alliteration?

Answer 1

You mean "what are the criteria for alliteration." Criteria is plural.

An alliteration is the use of a repeating consonant sound at the beginning of words. They do not need to be spelled the same. They do not need to be immediately adjacent, but any intervening words should be unaccented. "The Quran is kind to Christians" is an alliteration notwithstanding the unaccented words "is" and "to" and the fact that the same sound is spelled in three words with a "q", a "k", and a "ch".

On the other hand, "civic charity committee" is not an alliteration because although all three words start with "c" the "c" is pronounced differently in each word.