Yes, the least likely time to encounter carburetor ice is on the power reduction to l
BOLLOCKS
It's not the venturi which is the issue but the throttle butterfly (or plate).
At low power settings (as when on approach) the throttle plate is closed or nearly closed, restricting the air flow past the throttle body - which is when the maximum vacuum is being produced [or least indicated Manifold Pressure].
[30" Manifold Pressure = 0" Vacuum or 25" Vacuum = 5" MP]
[Indicated Manifold Pressure is measured in the induction manifold, not in the carburettor body]
A reduction of air pressure causes an adiabatic loss of temperature - remember your Meteorology lapse rate of 2 degrees Celsius per 1,000 feet of altitude for moist air, ie, at 10,000 feet you have lost 20 degrees of temperature.
Further to that, the carburettor design places the fuel idle jet and transition jet very near the closed throttle plate. To flow the fuel at these low throttle settings requires a reduction of pressure [increased vacuum] relative to the atmospheric pressure in the fuel bowl.
Fuel and/or water (moist air) being atomized has a refrigeration effect, further reducing the air temperature.
Dew Point - the temperature at which moist air become visible (Fog).
If you have a 20 degree day with a 10 degree Dew Point then you have visible moisture with a 5,000 feet reduction in pressure. A further 5,000 feet reduction in pressure equals freezing point.
At 10,000 feet, the air density is about half the sea level pressure - with a 20 degree loss of temperature.
Simple arithmetic will suggest that a increase of 15 inches of vacuum has reduced the air temperature by 20 degrees so you now have possible induction system icing. The throttle plate area will be even more subject to icing because the venturi effect is most marked in this area.
The modern pilot drives a fuel injected car - knows bugger all about carburettors - and when he/she climbs into the Warrior or 172 - has little knowledge about what's under the cowl. The younger instructor who teaches you everything you know - knows what!
Carburettor Icing can form at any OAT or any power setting - depending upon the humidity and temperature and throttle opening.
So the comment D) During the power reduction to land, there is the least chance of developing carb ice! There is the lowest power being applied and, therefore, the lowest temperature drop across the venturi! is the most misleading statement. Historical data shows it is where most carburretor icing is observed.
Follow the POH - and understand why!
Enjoy your tit-bits, Centaurus. Always thought provoking if you have sufficient brains to be prodded.