Answer:
The answer is your last option: by using humor when the mother suggests an exaggerated version or her previous statements about the weather reports
Step-by-step explanation:
As you may know, Irony is the humorous -often- expression to say something or mean something but generally means the opposite. In this case, let's discard the other options first: the other options cannot simple be possible as the three of them put an emphasis on "the weather" --conflict about weather forecasts, time affecting the weather situation, seasonal weather forecasts... and that's actually not the point in this excerpt knowing the purpose, which is explained above. On the other hand, as mentioned, irony is "humorous" thus, the fact that the mother is saying " be returned home to San Antonio by the strength of some Gulf winds!" apart of being humorous, it is also not and never possible to be returned by the wind! So that is irony!