Explanation: The time constant (τ) of a resistor-capacitor (RC) circuit is calculated by the formula τ = RC, where R is the total resistance and C is the total capacitance. First, determine the total capacitance. When capacitors are connected in parallel, their capacitances add together: C_total = 100 µF + 100 µF = 200 µF. Next, determine the total resistance. When identical resistors are connected in parallel, their equivalent resistance is half the value of a single resistor: R_total = 470 kΩ / 2 = 235 kΩ. Now, calculate the time constant using the total resistance and capacitance: τ = R_total × C_total τ = 235 kΩ × 200 µF To ensure the answer is in seconds, convert kilohms to ohms (× 10^3) and microfarads to farads (× 10^-6): τ = (235 × 10^3 Ω) × (200 × 10^-6 F) τ = 47,000 × 10^-3 seconds τ = 47 seconds. Therefore, the time constant is 47 seconds. Options A, C, and D are incorrect as they do not account for the proper combination of parallel components or unit conversions.