Final answer:
An E-7014 electrode can be used in all positions, not just flat or vertical. This type of electrode is versatile and designed for various welding angles and orientations.
Step-by-step explanation:
The E-7014 electrode is designed for welding in multiple positions. Although the information given about the current conducted by the solution is more related to chemistry and does not directly pertain to the use of electrodes in welding, based on the characteristics and typical use of E-7014 electrodes, we can infer their application. The correct answer to the question regarding the positions in which an E-7014 electrode can be used is c. All positions.