Concept:A microcomputer is a complete computer system built around a microprocessor, but the microprocessor itself is only one part of the system.
Explanation:Option A claims that a whole microcomputer can be placed on a single silicon chip.
This is false because only the microprocessor or CPU is fabricated on a single silicon chip.
A complete microcomputer still needs memory, storage, input/output ports, and support circuitry.
Option B is true because modern microcomputers can outperform older mainframe models.
Option C is true because ROM chips can permanently store program instructions in microcomputers.
Option D is true because most microcomputers today use rigid disk drives rather than floppy disk drives.
Therefore, the only incorrect statement is option A.
Answer:A. A microcomputer can be placed on a single silicon chip.