Here's a problem to solve: Company X makes 100 custom buses each year. Company Y makes 10,000 of one type of bus each year. Which of the following is the most likely reason a customer would buy a bus from company X instead of company Y?

Among the 4 following options, which is the correct answer?

- A: to keep the cost of the bus low
 
- B: to ensure that the bus will be easy to replace
 
- C: to provide ideas about how the bus will be built
 
- D: to ensure that people know how to drive the bus
 