9-43F5 B
 Which of the following statements about an NMEA -0183 system is correct? 
A. The cable shield must be grounded at both ends including the opto-isolators.
B. Opto-isolators must be used and the shield should be grounded to the talker chassis only. 
C. Opto-isolators must be used and the shield should be grounded to the listener chassis only.
D. Version 2 devices use higher voltages than version 1 devices.
