Which of the following is suitable as a description of supercomputers?
a) The number of bits that can be handled at the same time by the accumulator inside the processor is extremely large, which improves character string processing performance.
b) Large-capacity hard disk devices and virtual storage technology are used to realize an extremely large memory capacity and improve performance.
c) Hardware circuits that are specialized for specific application fields are separately provided and combined according to their purposes in order to improve performance.
d) Performance is improved by joining together several to 10-odd processors containing vector instructions, or several hundreds to several thousands of microprocessors.