Final answer:
Fast food is a popular dining option because it is relatively efficient and economical.
Step-by-step explanation:
The service that has become a popular dining option because it is relatively efficient and economical is fast food. When people are busy and under pressure, they often turn to fast food instead of eating home-cooked meals. Fast food restaurants offer quick service, allowing customers to get their meals in a short amount of time. Additionally, fast food is often cheaper than dining at a sit-down restaurant, making it an economical choice.