The correct answer is B: Lightning charge dissipation. The primary function of an external earth connection or ground rod is lightning charge dissipation - providing a safe path for lightning strikes to flow into the ground, protecting equipment and structures. Ground rods are primarily safety devices for lightning protection. When lightning strikes, the ground rod provides a low-resistance path for the massive electrical current to flow into the earth, preventing damage to equipment, structures, and people. While ground rods can also help with RF grounding and static buildup, their primary and most critical function is lightning protection. A proper ground rod system is essential for any antenna installation, especially tall structures like towers. The ground rod must be properly installed and connected to provide effective lightning protection.