Final answer:
Idling for more than five minutes primarily wastes fuel and increases emissions; however, it is not typically associated with clogging fuel injectors. Cars are increasingly more fuel efficient and don't require extended idling, even in cold weather.
Step-by-step explanation:
Idling for longer than five minutes can lead to several negative outcomes, including wasting fuel, increased emissions, and potential engine and vehicle systems issues. However, it does not specifically clog fuel injectors, so the correct answers to the question are: a. Waste fuel and b. Increase Emissions.
Modern cars are becoming more fuel efficient, which means they are designed to get more miles to the gallon and generally perform better in terms of fuel consumption. Additionally, in cold conditions, such as an exceptionally cold winter, car owners might idle their vehicles to warm them up, but this could lead to unnecessary fuel waste and higher emissions. Advances in technology mean that many modern cars can operate efficiently without the need for prolonged idling, even in cold weather.