Explanation: The average power of a pulsed RADAR transmitter is determined by its peak power and duty cycle. The duty cycle represents the fraction of time the transmitter is actually emitting a pulse. The duty cycle (D) is calculated as: D = Pulse Width (τ) × Pulse Repetition Frequency (PRF) Given: Pulse Width (τ) = 1 microsecond = 1 × 10⁻⁶ seconds PRF = 400 Hz Duty Cycle = (1 × 10⁻⁶ s) × (400 Hz) = 0.0004 The average power (P_avg) is then: P_avg = Peak Power (P_peak) × Duty Cycle Given: Peak Power (P_peak) = 100 kilowatts = 100,000 watts P_avg = 100,000 W × 0.0004 = 40 watts. Therefore, the average power of the RADAR transmitter is 40 watts. Options A, C, and D result from incorrect application of the formula or mathematical errors.