【Analysis】(1) When the ride distance does not exceed 3 kilometers, the charge is 12 yuan, and the average price per kilometer is at least 4 yuan (only when traveling 3 kilometers).
(2) When the ride distance does not exceed $3^{\sim} 10$ kilometers, due to $2.63.02$, the average price per kilometer will increase, and when traveling 10 kilometers, the average price per kilometer is the lowest and is 3.02 yuan.
Plan two has the lowest average price per kilometer, so Plan two is the most cost-effective plan.
【Answer】Plan two
2. BAIYUN Taxi charges a starting fee of 12 yuan for the first 3 kilometers (including 3 kilometers); from 3 kilometers to 7 kilometers (including 7 kilometers), it charges 2.6 yuan per kilometer; for distances greater than 7 kilometers, it charges 3.5 yuan per kilometer; now Yueyue needs to go to a place 30 kilometers away, with 3 options:
Option one: Take the first car for 15 kilometers, then switch to another car for 15 kilometers;
Option two: Change to a new car every 10 kilometers;
Option three: Do not fix the distance for changing cars, but each trip must be more than 3 kilometers.
Which option is the most cost-effective? Explain your reasoning.