单选题 According to the passage, which of the following is true concerning optical computers?

• (A) Researchers have not yet discovered a means of transporting photons more efficiently.
• (B) Their primary limitation is the density of connections required between electronic microchip gates.
• (C) Their accuracy level is poor at 8 to 11 bits, but still superior to that of electronic computers.
• (D) They invariably rely on electronic circuits to preprocess input data for computation.
• (E) Both analog and digital forms of optic computing are presently being developed by scientists.