I have a question about the following sentence:

> お母さんが、八百屋で長いこと、 **何を買うか** 決まらず迷っています。

Is it possible to replace "か" with "のか" without misunderstanding in this
sentence? Namely,

> お母さんが、八百屋で長いこと、 **何を買うのか** 決まらず迷っています。
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2017-11-27T06:10:06.287
54792
2017-11-27T12:45:01.107
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question
particles particle-か
Word choose between か and のか
This の is called "explanatory-no". Its basic role is to provide an explanation
for the current background context. When it's used with the question marker か,
のか seeks clarification or explanation for the current context.

  * [Explanatory のだ （んだ）](https://www.wasabi-jpn.com/japanese-grammar/explanatory-noda/)
  * [Question Markers: か and の](https://www.wasabi-jpn.com/japanese-grammar/question-markers/)
  * [What is the meaning of ～んです/～のだ/etc?](https://japanese.stackexchange.com/q/5398/5010)
  * [How is the "のです" working here?](https://japanese.stackexchange.com/q/3349/5010)

As described in the second link, の can form a casual question even without か,
although in this case か is required since it's in an [embedded
question](https://japanese.stackexchange.com/a/13038/5010).

That said, in this specific case, I think both sentences are almost completely
interchangeable, with or without の. Maybe the latter sounds slightly more
emphatic or emotional.

On the other hand, の is almost mandatory in the following context:

> お母さんは八百屋で30分も買い物をしていた。何を買った **の** か知りたい。

This is a typical case where の is used to seek clarification.
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2017-11-27T12:45:01.107
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2017-11-27T12:45:01.107
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answer