Passengers holding a(n)________ ticket cannot board the plane as it doesn’t specify the time of departure and on which the seat is also unconfirmed.

With an unconfirmed irrevocable letter of credit, ___________. A: the terms and conditions can be amended or cancelled unilaterally by any party B: only the exporter can amend the credit C: the advising bank transmits details without commitment to the beneficiary D: the issuing bank has the ability to cancel the credit at any time