A standard for DEP requires that a pilot can see how many seconds of distance at approach speed within a 1200m cutoff?

The standard for Decision Height (DEP) stipulates that a pilot should be able to see an adequate visual reference to ensure safety during the approach phase of landing. When the cutoff distance is set at 1200 meters, the reference criteria typically require that the pilot must be able to see the runway or other relevant visual cues for at least three seconds at approach speed.

This three-second visual reference is crucial because it provides pilots with enough time to assess the landing environment, make necessary adjustments, and initiate a go-around if conditions are not favorable for a safe landing. The three seconds allow for situational awareness, giving pilots the chance to respond effectively to any changes they may see as they approach the runway.

The other choices do not meet the established safety standard that enhances decision-making and situational awareness. Therefore, the three seconds is the required threshold, making it the correct answer.