Why Reactance is the AC opposition produced by energy storage in capacitors (electric field) and inductors (magnetic field), symbol X, measured in ohms. Unlike resistance it depends on frequency: inductive reactance XL = 2*pi*f*L rises with frequency, while capacitive reactance XC = 1/(2*pi*f*C) falls with frequency. It opposes current without dissipating power as heat, because the stored energy is returned to the circuit each cycle.
Watch out The choice about direct current and resistance describes plain resistance instead; reactance only shows up with changing (alternating) current, and the two 'reinforcement' choices are backwards since reactance opposes rather than helps current flow.
Reactance = AC resistance from L and C. Measured in ohms, but stores energy rather than burning it.