单选题 Although costs are falling, wheel motors are generally more expensive than conventional drivetrains, and they don't handle as well as conventional cars. Wheel-motor vehicles may not catch on in a big way for a decade or so, but improvements in the technology and the push for efficiency could transform ring magnets into a new standard for powering cars.
What is the reason that wheel motors will no| catch up with traditional cars soon?

• A. Wheel motors are more expensive and prices are still rising.
• B. Wheel motors are not as easy as traditional cars to use.
• C. The technology is not making improvement at present.
• D. The technology cannot save as much energy as expecte