Change the narration: The secretary said, "Is Mr. Hyder in his office?"

The secretary asked if Mr. Hyder had been in his office.

The secretary said that if Mr. Hyder was in his office.

The secretary enquired if Mr. Hyder was in his office.

None of these

Direct: The secretary said, "Is Mr. Hyder in his office?"

It’s a yes/no question, so:

"said" becomes enquired

The question is changed to a statement structure

Present tense is becomes past was

Use if or whether for indirect questions

So,

Indirect: The secretary enquired if Mr. Hyder was in his office.