Final answer:
A corroded or burned connector terminal is the most common cause of high circuit resistance.
Step-by-step explanation:
A corroded or burned connector terminal is the most common cause of high circuit Resistance.
When a connector terminal becomes corroded or burned, it creates an unintended resistance in the circuit. This increased resistance restricts the flow of current in the circuit, resulting in a high circuit resistance. An example of this can be seen when worn insulation on wires of a toaster allows them to come into contact with a low resistance, causing thermal power to be created rapidly and potentially melting or burning the cord.
Therefore, the correct answer is A) Resistance.