Option B is correct. The order of oxidizing power is F > O > Cl > N. Fluorine is the most electronegative element and thus the strongest oxidizing agent. Oxygen, being in the same period as fluorine, also exhibits high oxidizing power, though less than fluorine. Chlorine has less electron-electron repulsion in its larger $n = 3$ quantum level compared to the $n = 2$ level of O and F, but its overall oxidizing power is less than oxygen. Nitrogen has the lowest oxidizing power among these elements.