One problem our industry has is a lot of people suffer from out-of-date knowledge. This is a technical field, so the right answer, solution, or technology changes over time.
Take Tavcom training's question:
This is the equivalent of asking - fax machines or mobile phones - what is more commonly used? This is a question that made sense 15 years ago but it's absurd today. CMOS is dominant and has been dominant for years. The meaningful choices are amongst CMOS sensors, not whether it's CMOS or CCD. Related: Surveillance Camera Imager Tutorial
And then you have Tavcom, which is the largest UK training provider, who does not get this. Recall, they are the same company that produced a video claiming you are limited to about 7 HD cameras on an IP system because of a 'lack of bandwidth.'