Answer:
The correct answer is option 3.
Explanation:
The average cost per mile is $0.50.
It includes sunk cost such as the cost of insurance.
When a rider offers to pay less than the average cost for a ride the driver still accepts it. This is because the insurance cost is a fixed cost it does not increase with the increase in driving. The driver only needs to cover the variable cost through fare. So even if he is getting less than $0.50 from the rider, it will be accepted as the variable cost is being covered.