As Glenn says, it's a poorly formulated question precisely because it creates the ambiguity that you describe.
I don't know who wrote this question and what they are trying to accomplish. In context it sounds like the person who wrote the question was just careless. But such questions are a pretty standard technique in opinion polls or surveys by people trying to get a pre-determined result: Word a question in such a way that you push people to give the answer you want, but then put out a press release where you don't quote the exact question.
Like, a few years back I saw news stories about some survey that found that the "traditional American family" was pretty much dead, with only some tiny percentage of Americans fitting that definition. The news stories talked about all the alternative family arrangements that were becoming more popular: from second marriages with children from prior marriages to people living together without marriage, homosexual couples, etc. But they never defined exactly what they called a "traditional family". I finally found one news story that gave the definition they used for the study: two married people of the opposite sex with two children from that union sharing a home. So if you had three children: not a traditional family. If you were a newlywed couple who hadn't had children yet or if your children were grown and moved out: not a traditional family. If you were married for 60 years and your spouse died: not a traditional family.
My point with that example isn't to take a position on social issues -- that was just one example, I've seen plenty from all over the map. My point is that when constructing a question where you are trying to solicit opinions, you have to be careful to distinguish whether you are asking about a general principle or a detail, and in general to make clear just what you are asking.
If I was given such a question in the context that you are describing, an essay question, I think one easy way out would be to acknowledge the stated number so that the examiner cannot say that you misread the question, and then dismiss it. Like if you were for term limits, say, "We could debate the exact time, whether it should be the five years stated in the question or some slightly longer or shorter term, but ..." If you are against term limits in principle, I think I'd make clear that it is not the specific number that you are objecting to, but the concept. i.e. you are not rejecting five years because you think it should be seven years or two years, but because you think there should be no limit at all. Alternatively, if you think that the length of the limit is a crucial question, than say that. Like make clear why less than three years is just too short but more than four years is too long or whatever.
But if you are forced to say "yes" or "no", then the question is meaningless and almost unanswerable. Like the classic, "Have you stopped beating your wife?"