Option 1: Increasing the current in the filament will affect the intensity of the X-rays but not the penetrating power. The current in the filament determines the number of electrons being produced, which in turn affects the intensity of the X-rays. However, it doesn`t directly impact the penetrating power.

Option 2: Decreasing the potential difference between the cathode and the anode will actually decrease the penetrating power of X-rays. The potential difference determines the energy level of the electrons and, therefore, the energy of the X-rays produced. Decreasing the potential difference will result in lower energy X-rays with lower penetrating power.

Option 3: Decreasing the current in the filament will decrease the intensity of the X-rays, but it won`t directly affect the penetrating power. The current in the filament determines the number of electrons being produced, which affects the intensity of the X-rays. However, it doesn`t directly impact the penetrating power.

Option 4: Increasing the potential difference between the cathode and the anode increases the penetrating power of X-rays. The potential difference determines the energy level of the electrons and, therefore, the energy of the X-rays produced. Increasing the potential difference will result in higher energy X-rays with higher penetrating power.

Therefore, the correct answer is