The more likely cause of an electrical connection heating up is corroded connectors, which increase the resistance and the power dissipated as heat. Overcharging a battery, too large wire gauge, or a blown fuse would not typically result in such heating.
The more likely cause of an electrical connection heating up is c) corroded connectors. This happens because corrosion can increase the resistance of the connection (Rw), which in turn increases the power dissipated (P = I²Rw) as heat when current (I) flows through it. The other options such as a wire gauge being too large would actually reduce resistance, an overcharged battery doesn't directly cause connections to heat up but could lead to increased current flow, and a blown fuse would break the circuit, preventing current from flowing, which would not cause heating.
In summary, an electric wire or connector may overheat if the current it carries exceeds its capacity, or if its resistance increases due to factors like corrosion. Some appliances may have increased resistance due to wear, such as a worn appliance cord, which leads to excessive heat generation. To prevent the dangers associated with overheating, fuses and circuit breakers are used to automatically interrupt the excessive flow of current.