Що таке Ольстерська проблема ( визначення ) ?

Какие времена английского глагола употреблены в шутке?

"little boy" says a man, "why are you carrying that umbrrella over your head? It is not raining."

"I'm carrying it now" says the boy, "decause when it rains Father wants it? and so I can take it only when the weather is fine." 

A) Present Continuous, Past Simple

B) Present simple, Present Continuous