Explanation: The MTI (Moving Target Indication) circuit is a critical component in radar systems designed to differentiate moving targets from stationary clutter. It functions by detecting the Doppler shift in the reflected radar signal. Moving targets cause a slight frequency change (Doppler shift) in the radar's echo, while stationary objects produce echoes with no frequency shift. The MTI circuit acts as a specialized filter that compares successive received pulses. It effectively blocks or suppresses the constant echoes from stationary objects like buildings, hills, or ground clutter, allowing only the signals from moving targets to pass through and be displayed. Therefore, option B is correct because the MTI circuit filters out stationary targets, making moving targets more easily detectable. Options A, C, and D describe unrelated or opposite functions.