Final answer:
The conditions necessary for the sustained flow of water in a pipe and charge in a wire are pressure and voltage respectively. Option A) Pressure; Voltage is the correct answer.
Step-by-step explanation:
The condition necessary for the sustained flow of water in a pipe is pressure, while the analogous condition necessary for the sustained flow of charge in a wire is voltage. Therefore, the correct answer to the question is A) Pressure; Voltage. Water at a higher pressure moves through the pipe much like charges move from a region of higher electric potential (voltage) to a lower one. Just like a water pump creates a pressure difference to move water through a circuit, a battery provides a voltage difference to push the electric charges through an electrical circuit. This similarity illustrates how concepts in fluid dynamics can be analogous to those in electrical circuits.