Pradeep got my point but I think J Isberg really nailed the answer. The key
word is "must". A throws clause is an alternative to a try block.
I hope this kind of question is not on the
SCJP exam. It's more like a riddle than a
test of knowledge. Somone who is well aware of throws clauses (like myself and the other above posters) were fooled by the wording into answering a different question than the one asked.
Some misleading items, like incorrect indentation and deceptive naming of class references, are realistic reflections of life as a programmer. Tricky wording of questions is just an easy way to get some spread in the scores.