Question

He replied"I don't know"
Change this sentence to indirect speech.

Answer 1

He says that he doesn't know.

I'm pretty sure this is right but idk for sure.

Answer 2

He told that he didn’t know.

In a direct speech, whatever somebody says is put within quotations.

But in an indirect sentence it is a reported speech and what the person says is told in an indirect report-like manner.

So in this case, his reply that he did not know is told as an indirect speech.  

I don’t know is in present tense.