Jack comes to work every day and sees Olivia working at the office. Jack usually asks Olivia, "What's the date today?" and "What day is it today?" because she is good at keeping track of days while Jack is quite careless in this regard.
On September 23rd, however, Olivia must have had some negative happening to her. Jack asked her those two questions, but she didn't answer them right away. A few months later Olivia went missing.
Jack is sitting at the police office now and the detective is asking Jack when the first time was when Jack had noticed something strange in Olivia's behaviour? Jack right away recalls September 23rd.
Jack answers, "It was on September 23rd. It was the first time when she wasn't able to answer my usual questions about..."
How should I continue here?
Here I have some options:
1) "... about that day's date and day";
2) "... today's date and day on that day";
3) "... the current date and the day";
4) "... the date and the day of that day";