An amber DSPLY SOURCE annunciation below each speed tape indicates:
A.A.The altimeter is receiving inputs from a source other than the ADIRU and should be considered unreliable unless verified by another source
B.B.A single DEU has been manually or automatically selected to drive all six display units
C.C.A non-dispatchable CDS fault has occurred
D.D.A single EFIS control panel has been manually or automatically selected as the source for all six display units
正确答案是B