Your diesel engine does not start in winter. What can be the reason for this?

You chose the correct answer. Diesel engines can have trouble starting in winter if there is summer diesel fuel in the tank, because summer diesel can become waxy and clog fuel lines or filters at low temperatures. Unlike gasoline engines, diesel engines do not use spark plugs or ignition cables, so issues with those are not relevant for diesel starting problems. For future questions, remember that diesel engines rely on compression and proper fuel properties for ignition, especially in cold weather.