Choose the most suitable option to replace the highlighted part of the sentence: No one knows where is he hiding.

Correct — C. After knows, 'where he is hiding' is not a question but the object of the verb — an embedded question.

An embedded question takes statement order, subject before verb: 'where he is hiding', not the question order 'where is he hiding'.

The verb itself, the progressive 'is hiding', stays as printed → option (c).

Why the others are wrong

• (a)
  where is he hide — Keeps the inverted is he and breaks the verb as well: after is, the progressive needs the -ing form, so 'is hide' is not English.
• (b)
  where he is hiding at — The word order is fixed, but at is redundant. Where already means 'in what place', and a trailing at is colloquial, not standard written English.
• (d)
  where he has hidden is — 'No one knows where he has hidden is' has a verb too many. 'Where he has hidden' is already a complete clause, so the trailing is has no subject.

A question placed inside a larger sentence — after know, wonder, ask, tell me — is an embedded (indirect) question. It works as a noun clause, so it keeps ordinary statement order: wh-word, subject, verb.

Direct: 'Where is he hiding?' Embedded: 'No one knows where he is hiding.'

The auxiliary moves behind the subject, and a question mark appears only if the whole sentence is a question: 'Do you know where he is hiding?'

Key facts

• An embedded question uses statement order: 'where he is hiding', not 'where is he hiding'.
• Inversion of subject and auxiliary belongs to direct questions.
• Where means 'at or in what place', so standard written English adds no at after it.

Common traps

• Keeping the question order because the clause begins with where, as a direct question does.
• Picking 'where he is hiding at' because its word order is right — the extra at is the fault.

No directly related past PYQ was found.