; or (2) accept any voucher, credit, or other form of compensation offered by the air carrier or foreign air carrier pursuant to subsection (c). (b) Timing of refund Any refund required under subsection (a) shall be issued by the air carrier or foreign air carrier— (1) in the case of a ticket purchased with a credit card, not later than 7 business days after the request for the refund; or (2) in the case of a ticket purchased with cash or another form of payment, not later than 20 days after the request for the refund. (c) Alternative to refund An air carrier and a foreign air carrier may offer a voucher, credit, or other form of compensation as an alternative to providing a refund required by subsection (a) but only if— (1) the offer includes a clear and conspicuous notice of— (A) the terms of the offer; and (B) the passenger's right to a full refund under this section; and (2) the voucher, credit, or other form of compensation remains valid and redeemable by the consumer for a period of at least 5 years from the date on which the voucher, credit, or other form of compensation is issued. (d) Significantly delayed or changed flight In defining significantly delayed or changed flight for purposes of this section, the Secretary shall ensure that such term includes, at a minimum, a flight where the passenger arrives at a destination airport— (1) in the case of a domestic flight, 3 or more hours after the original scheduled arrival time