the phrase \open circuit\ means\na loose wires.\nb disconnected.\nc fully charged.\nd current can flow free.

Brief Explanations:

In an open - circuit, the electrical path is broken, which means it is disconnected and current cannot flow. Loose wires may or may not cause an open - circuit, fully charged is unrelated to the concept of an open - circuit, and in an open - circuit, current cannot flow freely.

Answer:

B. disconnected