An adjective for a question that is right on the nail?

Is there any adjective in English that could describe a question (or a remark, an assessment) that is the perfect and the most pertinent question to ask in a given situation, hits the nail right on the head, thus steering the conversation onto the right track?

I'm looking for a clean way to express Japanese ズバリ (as in: ズバリな質問). The literal dictionary translation is: "1. decisively; decidedly; boldly; once and for all; unreservedly; frankly 2. precisely; exactly". I've tried looking up that word in the dictionary and scrolling through a bunch of example sentences, but I can't find a single word solution.

For instance: 彼の言葉はズバリ急所を言い当てた。=> "His remark hit home." The issue is that the word comes as a descriptor of his remarks here, so I'm looking for a single-word equivalent that fits that role: "His remark was ________"

arresting adj OED

That arrests; that takes hold of the attention; striking.

As in: Let Justice Roll: Prophetic Challenges in Religion, Politics, and Society GoogleBooks

Walker Percy asks, and it is an arresting question for an age in which attaining happiness has become something like a point of honor.

As a police arrest, when something is arresting, it captures your attention because it is incisive, bold and mesmerizing.

Incisive would work for this question too.