Which of the following is true about Bille's lense

单项选择题

A new high-performance contact lens under development at the department for applied physics at the University of Heidelberg will not only correct ordinary vision defects but will enhance normal night vision as much as five times, making people’s vision sharper than that of cats.
Bille and his team work with an optical instrument called an active mirror -- a device used in astronomical telescopes to spot newly emerging stars and far distant galaxies. Connected to a wave-front sensor that tracks and measures the course of a laser beam into the eye and back, the aluminum mirror detects the deficiencies of the cornea, the transparent protective layer covering the lens of the human eye. The highly precise data from the two instruments -- which, Bille hopes, will one day be found at the opticians (眼镜商) all over the world -- serve as a basis for the production of completely individualized contact lenses that correct and enhance the wearer’s vision.
By day, Bille’s contact lenses will focus rays of light so accurately on the retina (视网膜) that the image of a small leaf or the outline of a far distant tree will be formed with a sharpness that surpasses that of conventional vision aids. by almost half a diopter (屈光度). At night, the lenses have an even greater potential. "Because the new lens -- in contrast to the already existing ones -- also works when it’s dark and the pupil is wide open," says Bille, "lens wearers will be able to identify a face at a distance of 100 meters" -- 80 meters farther than they would normally be able to see. In his experiments night vision was enhanced by an even greater factor: in semi- darkness, test subjects could see up to 15 times better than without the lenses,
Bille’s lenses are expected to reach the market in the year 30, and one tentative plan is to use the Internet to transmit information on patients’ visual defects from the optician to the manufacturer, who will then produce and mail the contact lenses within a couple of days. The physicist expects the lenses to cost about a dollar a pair, about the same as conventional one-day disposable lenses.

Which of the following is true about Bille's lenses（）

A．They will be sold at a very low price.
B．Their production process is complicated.
C．Purchase orders can be made through the Internet.
D．They have to be replaced every day.