Which situation is the best example of irony?

A baker is allergic to the most important ingredient.

An actor collapses from stress during a performance of a play.

A writer scraps a draft of his novel, unsatisfied with it.

A baker is allergic to the most important ingredient.

This situation is the best example of irony as it involves a baker, whose profession depends on using a certain ingredient, being allergic to that very ingredient. It is ironic that the person best suited to work with the ingredient is unable to do so due to a medical condition.