(a) The notice of funding opportunity sets the deadline date and method(s) for applications to be submitted to the Institute.

(b) If the application notice permits mailing of an application, an applicant must be prepared to show one of the following as proof of timely mailing:

(1) A legibly dated U.S. Postal Service postmark.

(2) A legible mail receipt with the date of mailing stamped by the U.S. Postal Service.

(3) A dated shipping label, invoice, or receipt from a commercial carrier.

(4) Any other dated proof of mailing acceptable to the Director.

(c) If the application notice permits mailing of an application, and the application is mailed through the U.S. Postal Service, the Director does not accept either of the following as proof of mailing:

(1) A private metered postmark.

(2) A mail receipt that is not date cancelled by the U.S. Postal Service.