The option that is not a potential risk of purchasing a used car is:
C. Used cars can have a lower initial cost.
A. Used cars can require repairs sooner. This is indeed a potential risk because older vehicles may have more wear and tear, leading to a higher likelihood of needing repairs.
B. Shorter lifespans of the engine and transmission. This is another risk associated with used cars, as older vehicles may have components that are closer to the end of their life expectancy.
D. Unexpected issues may arise. This is also a potential risk since used cars may have hidden problems that are not immediately apparent at the time of purchase.
However, C. Used cars can have lower initial cost, is not a risk but rather an advantage or benefit of purchasing a used vehicle. While lower initial costs can lead to savings, they do not imply any risk associated with the vehicle's condition or performance.