Orifice tubes are A. coded in American models only. B. coded by number for easy identification. C. similarly but not exactly sized. D. universally sized

I'd go for (C) similarly but not exactly sized

Basically, to explain an orifice tube in Layman’s context, it is a car’s air conditioning system and is the exact place where the cold happens. Not all orifice tubes are standard sized and this means that different model vehicles use different sizes. These tubes are often color-coded for easy identification.