What type of conductor is a large, low-resistance device connected in parallel with meter terminals?

The correct answer is the shunt. A shunt is a specialized low-resistance conductor that is used in parallel with a measuring instrument, such as an ammeter. Its primary function is to allow a specific portion of the current to bypass the meter, thus enabling the measurement of high current levels without damaging the instrument. By using a shunt, only a small, manageable amount of current flows through the meter, while the majority continues through the shunt. This arrangement allows for accurate measurement of high-current applications while protecting delicate components within the meter.

Load resistors, while also related to resistance, usually serve different purposes, such as adjusting voltage or limiting current in a circuit. A thermistor is a temperature-sensitive resistor that changes its resistance with temperature, which is not applicable in this context of parallel connections for current measurement. A rectifier, on the other hand, is a device that converts alternating current (AC) to direct current (DC) and does not function in the capacity of measuring or shunting current in parallel with meters. Thus, the shunt is specifically designed for the application described in the question.