The correct answer is A) an extended meter range. When a resistor is used as a shunt and connected in parallel with a meter movement coil, it allows the meter to measure a greater range of current than it would be able to measure on its own. The shunt resistor diverts some of the current away from the meter movement, effectively extending the meter's range and allowing it to measure higher current levels. This provides the capability of an extended meter range, which is the primary purpose of using a shunt resistor in this configuration. The other answer choices are incorrect because: B) a shunt resistor does not measure circuit resistance, C) it does not increase the accuracy by 1.5%, and D) using a shunt resistor with a meter movement is a common and useful practice.