Aheadline sounds the most credible when it:

Headlines sounds credible if the writer will be using the question, is reading this article be beneficial for me. Using this question, the headline sounds credible and audience will have the curiosity to read the article. Also having a good headline makes the reader attracted to read it. so if your looking for something shorter its Formal language

It is clear, formal, and familiar

Explanation:

A convoluted headline is often just ignored or taken as unlikely. We can see many examples of it during the politically invested election times. Formal statement sound more believable because they sound like they have gone through a professional procedure before being publish. And familiar things are believable because everybody can believe that something that they know to have happened one before has happened again, even if it's unlikely to.

i think its a.

an ugly duckling is teased by the other ducklings. when she grows up, however, the ducklings discover that she is a beautiful swan