I think C is most appropriate , because There is a flag called IEN ( Interrupt enable ) Flag which is set to 1 when an interrupt arrives .
but as soon as you serviced the interrupt , and when the contents of interrupted process are restored till that time IEN is disabled so that no other interrupts can arrived or set the IEN flag .
As soon as the restoring is done , interrupted process is executed and then ( IEN is enabled ) so it may happen that happen that another higher priority interrupt . But if you see there may be small time but it is always case that interrupted process will be excuted ( may be for very short time if higher ones come ).