As you say, the question presented to Fry doesn’t mention a question at all. Only an answer. So, you could make an argument that any answer could be the answer to something, and therefore you’d have to choose a 100% chance, which isn’t an option.
On the other hand, it asks for the chance of “picking the correct one”, clearly meaning “the correct answer”. So, as there is no answer that is the correct answer to everything, the correct choice would be 0%, which is an option.
As you say, the question presented to Fry doesn’t mention a question at all. Only an answer. So, you could make an argument that any answer could be the answer to something, and therefore you’d have to choose a 100% chance, which isn’t an option.
On the other hand, it asks for the chance of “picking the correct one”, clearly meaning “the correct answer”. So, as there is no answer that is the correct answer to everything, the correct choice would be 0%, which is an option.