A variable wind direction with a speed of 4 knots would be coded as?

The correct coding for a variable wind direction with a speed of 4 knots is represented as "VRB04KT." In meteorological observations, the shorthand "VRB" indicates that the wind direction is variable, which means it is changing and does not come predominantly from any specific direction.

The "04" denotes the speed of the wind, which in this case is 4 knots. The "KT" at the end specifies that the wind speed is measured in knots, a standard unit used in meteorology for wind speed. Therefore, when combined, "VRB04KT" succinctly conveys that the wind is variable at a speed of 4 knots.

The other options contain either extraneous information or incorrect representations. For instance, "VRB04GKT" suggests gusts are involved, which is not the case since only a steady speed is indicated. "VRB04" omits the "KT" tag, which does not comply with the coding standards that indicate the measurement unit. "VAR04KT" suggests a different meaning, as "VAR" is not commonly used in this context for reporting variable wind in the same manner as "VRB." Therefore, "VRB04KT" is the correct and complete format