信用证中的这个条款怎么理解?CERTIFICATE ISSUED BY CARRIER OR THEIR AGENT'S

信用证中的这个条款怎么理解?
CERTIFICATE ISSUED BY CARRIER OR THEIR AGENT'S CERTIFYING:SHIPMENT HAS NOT BEEN EFFECTED BY
A)TANKER VESSEL AGED BETWEEN 15-20 YEARS WHICH DO NOT HOLD ISM CERTIFICATE
B)TANKER VESSEL AGED OVER 20 YEARS,CARGO OR CONTAINER VESSEL AGED OVER 35 YEARS AND VESSEL WHICH ARE NOT CLASSED AS PER INSTITUTE CLASSIFICATION CLAUSE
C)CAMBODIA,BELIZE,GEORGIA,SAO TOME AND PRINCIPE FLAGGED VESSL