During the use of the battery pack, the appearance is normal, but there is no current during charging, the voltage drops to 0 at the moment of discharge, and the battery pack cannot be discharged. Which of the following situations may occur?

During the use of the battery pack, the appearance is normal, but there is no current during charging, the voltage drops to 0 at the moment of discharge, and the battery pack cannot be discharged. Which of the following situations may occur?
A . Open circuit in the battery pack
B . Sulfation
C . Backward battery
D . Battery leakage

Answer: A