Change the narration: "By God", he said "I do not know his name".

He said that by God he does not know his name.

He swore that he did not know my name.

He swore that he did not know his name.

None of these

He swore that he did not know his name.

"By God" expresses an oath → changes to "He swore that..." in indirect speech.

"I do not know" becomes "he did not know" (tense shift from present to past).

"His name" remains unchanged as the pronoun is consistent.