the date of interview

[impeccableman]

"Kindly confirm by email on or before 5:00 pm on the last Thursday before the date of interview, your attendance at the interview."

Q1: If the date of the interview is on 31st January (Saturday), Is it that I have to confirm by mail on or before 5:00 pm
on 29th January or 22nd January?

[Rusty]

"Kindly confirm by email on or before 5:00 pm on the last Thursday before the date of interview, your attendance at the interview."

Q1: If the date of the interview is on 31st January (Saturday), Is it that I have to confirm by mail on or before 5:00 pm
on 29th January or 22nd January?
The last Thursday before Saturday, January 31st is Thursday, January 29th.

[impeccableman]

thank you ^_^