Answer: A) A baker has a wheat allergy.
Explanation: an irony is a state of affairs or an event that seems contrary to what one expects and it often has an amusing result. A situational irony is when what happens is the contrary to what the characters or the audience are expecting to happen. From the given options, the situation that is the best example of an irony, is the corresponding to option A, because the fact that a baker (who works mostly with wheat flour) has a wheat allergy, seems contradictory.