Which of the following is a safety concern for the EF Johnson 5112?

The selection of battery pack usage when charging as a safety concern for the EF Johnson 5112 is accurate because improper handling or charging of battery packs can pose significant safety risks. When batteries are charged, they need to be monitored for any signs of overheating or malfunction, as these issues can lead to battery failures, leaks, or even fires in extreme cases. This highlights the need for users to follow specific guidelines when charging these batteries to ensure safety and prevent damage.

While transmitter overheating, water resistance, and signal interference are important considerations, they are less directly tied to the immediate safety concerns linked with the operation and maintenance of the device. Transmitter overheating is an operational concern, water resistance relates to environmental durability, and signal interference affects performance but may not directly relate to user safety.