问题：

[单选] If your bridge-to-bridge radiotelephone ceases to operate，you must（）.

A . immediately anchor your vessel and arrange for repairs to the system
B . moor your vessel at the nearest dock available and arrange for repairs to the system
C . arrange for the repair of the system to be completed within 48 hours
D . exercise due diligence to restore the system at the earliest practicable time