[单选题]

The last sentence means that a knowledge of fish sounds can help man to ______.
A． avoid confusion in fishing activity
B． avoid unneeded effort in fish sound studies
C． detect enemy submarines
D． pick up new sounds

The last sentence means that a knowledge of fish sounds can help man to ______.A． avoid confusion in fishing activityB． avoid unneeded effort in fish sound studiesC． detect enemy submarinesD． pick up new sounds