Select the correct direct form of the given sentence.

He told you that he had not known that it was your birthday that day.

He said to you, “I did not know that it is your birthday today.”

The correct direct form of the sentence "He told you that he had not known that it was your birthday that day" is He said to you, "I did not know that it is your birthday today."

The other options are incorrect:

• You said to him, "I do not know that it is your birthday today." This is incorrect because the speaker is "He" and the listener is "you."
• He said to you, "You did not know that it was my birthday today." This is incorrect because the speaker is "He" and the listener is "you."
• He said to you, "I did not know that it was your birthday that day." This is incorrect because the tense of the reported speech should be "today" instead of "that day."