The correct answer is B: Resistance circles and reactance arcs. A Smith chart uses a resistance circles and reactance arcs coordinate system. The chart is a circular graph with constant resistance circles and constant reactance arcs. The Smith chart has two families of curves: circles of constant resistance (horizontal circles) and arcs of constant reactance (curved arcs). Resistance circles are centered on the horizontal axis, with values from 0 (left edge) to infinity (right edge). Reactance arcs are curved lines representing inductive (upper half) and capacitive (lower half) reactance. Together, these circles and arcs form a grid where any impedance can be plotted as a point. The intersection of a resistance circle and a reactance arc gives you the impedance value.