Why A meter is the component whose whole purpose is to indicate the value of an electrical quantity such as voltage, current, or resistance, either with a moving pointer on a scale or as digits on a display. Multimeters, ammeters, and voltmeters all fall into this category. The other parts listed control or switch current rather than report it.
Watch out A potentiometer is tempting because it has a knob and a scale printed around it, but it is a variable resistor that adjusts a circuit, it does not measure or display anything.
Meter = measure. If the question asks what shows a number or reading, the answer is the meter.