Explanation: The resonant frequency (f) of a circuit, a foundational concept in radio theory, is the specific frequency at which an inductor (L) and capacitor (C) will exhibit their maximum combined impedance (in parallel) or minimum combined impedance (in series). This is where the inductive reactance (XL) equals the capacitive reactance (XC). The fundamental formula to calculate this frequency is f = 1 / (2π√(LC)). Here, L is the inductance in Henries, C is the capacitance in Farads, and f is the frequency in Hertz. Option A presents this exact fundamental formula. Option B, f = 0.159 / √(LC), is simply a numerically approximated version of the same formula. Since 1 divided by 2π (1 / (2 * 3.14159...)) is approximately 0.15915..., the value 0.159 is a rounded constant representing 1/(2π). Therefore, both formulas are mathematically equivalent and correctly determine the resonant frequency given inductance and capacitance.