I'm doing an informal interview through email. How should I politely say that I need the answers by the 21st?

Thank you in advance for your answers.
I'm doing an informal interview through email. How should I politely say that I need the answers by the 21st?
Attach a note that says, "Please respond by the 21st." If by the 20th, you haven't had all the responses you need, a reminder of "Please take a moment to respond." Should do.


:)
Reply:please reply by the 21st , thankyou
Reply:please reply by the 21st as there is a deadline for my interview.
Reply:"Please respond by the 21st."
babynames