If the exporter and the importer do not know each other well and are located in countries thousands of miles apart, which of the following terms of payment is the safest for the exporter?<br /> A、by D/P at sight<br /> B、by 30%T/T in advance, 70% D/P<br /> C、by an irrevocable L/C at sight<br /> D、by 30% T/Tin advance, 70% irrevocable L/C at sight