The standard rate of turn is

Standard rate turn (also called Rate 1 turn) is 3 degrees per second, which completes a full 360-degree circle in exactly 2 minutes (3°/s × 120s = 360°). This is the reference turn rate used in instrument flying procedures. The other options are incorrect - 6°/s would be a Rate 2 turn (30 seconds per circle), while 12°/s and 24°/s are not standard aviation turn rates.