Option (C) is correct. According to the textbook context, when a p-n junction is under forward bias, the p-side is connected to the positive terminal and n-side to the negative terminal of the battery. The direction of the applied voltage is opposite to the barrier potential. As stated in the text: 'In forward bias... the barrier is decreased while the barrier increases in reverse bias.' This happens because the applied voltage opposes the built-in potential barrier, effectively lowering it. When the potential barrier is lowered, majority carriers (electrons from n-side and holes from p-side) can easily cross the junction, resulting in significant current flow (in mA). Option (A) is incorrect because raising the potential barrier occurs during reverse bias, not forward bias. Option (B) is incorrect because forward bias increases the majority carrier current rather than reducing it to zero.