There is only one answer to that.

那只有一个答案。

《新英汉大辞典》

Only one answer I can think of.

我能想到的唯一答案。

youdao

There is only one answer.

答案只有一个。

youdao

What is this orbital? Yup. And there's only 2pz one correct answer here, which is to 2 p z.

它的轨道是什么？，嗯，这里,只有一个答案，那就是。

麻省理工公开课 - 化学原理课程节选

Everyone knows from calculus that if you're trying to find a function about which you know only the derivative, you can always add a constant to one person's answer without changing anything.

学过微积分的人都知道,如果你想根据已知的导数,求出其原函数,你总是可以给某人的答案,随便加一个常数,且不影响结果

耶鲁公开课 - 基础物理课程节选

The former has only one answer, and is not context relevant.

FORBES: IBM's Watson Jeopardy Stunt Unleashes a Third Great Cycle in Computing

If to bean or not to bean is the question, in Texas there is only one answer, typically delivered at length and in a tone of outraged disbelief.

BBC: The perfect chilli con carne in the heart of Texas

In the context of Quora it seems most of the experience is designed around this, though there are subtle things that make it special like the ability to provide only one answer per question.

FORBES: Why Is Quora Exploding?