What causes junction potential in a potentiometric setup, and how can it be minimized?

• A. It is caused by temperature fluctuations and can be minimized by maintaining constant temperature.
• B. It is caused by pressure changes and can be minimized by using a pressure regulator.
• C. It is caused by ion size differences and can be minimized by using ions of similar size.
• D. It is caused by light exposure and can be minimized by using opaque containers.

Answer: (C)