Question 990Navigation General

The correct answer is B) sensitivity time control (sea-clutter control). The sensitivity time control (STC) or sea-clutter control is the radar control that reduces weak echoes out to a limited distance from the ship. This control adjusts the receiver gain to reduce the effect of sea clutter, which are the radar returns from the waves and wake of the ship. By reducing the gain at shorter ranges, the STC helps to suppress these weaker echoes and improve the visibility of other targets. The other options are incorrect because they serve different functions - the fast time constant is used to reduce the effect of rain or other atmospheric clutter, the receiver gain control adjusts the overall sensitivity of the radar, and the brilliance control sets the display brightness, but does not directly affect the reduction of sea clutter.