Which of the following statements about current flow is true?

The statement that current flows from negative to positive is rooted in the historical convention established by Benjamin Franklin, who assumed a flow of positive charge. In reality, the actual charge carriers in conductive materials, particularly metals, are electrons, which move from the negative terminal to the positive terminal. However, conventional current is defined as moving from positive to negative. This can sometimes cause confusion, but since the question asks for the true nature of current flow, it is important to recognize that "currents" are indeed often described as flowing from the negative side, acknowledging the electrons' actual movement as they provide the electric charge.

The other options present misunderstandings or inaccuracies about current flow. The assertion about the conventional current flow principle being always accurate overlooks the exception posed by actual electron flow. Similarly, stating that current can only flow in one direction does not account for alternating current (AC), where the flow of current changes direction cyclically. Lastly, the claim that current does not flow in circuits is inherently incorrect, as current is the very essence of what allows circuits to function.