It is an irrevocable letter of credit which can not ( ).

A．stacking test；rolling test；vibration test
B．rolling test；stacking test；vibration test
C．vibration test；stacking test；rolling test
D．rolling test；vibration test；stacking test

A．animal and plant quarantine；ante-mortem veterinary inspection
B．ante-mortem veterinary inspection；animal and plant quarantine
C．animal and plant quarantine；detection of defects
D．detection of defects；ante-mortem veterinary inspection