Basic components of a computer system

The governing concept is bus bandwidth. A data bus provides the path through which data moves between the processor, memory and other components. A narrow bus carries fewer bits in one transfer cycle, so the fast CPU may have to wait for more transfer cycles before receiving or sending all required data. Thus option B is correct. Monitor brightness, printer speed and the number of keyboard keys do not determine the width of the data path.

The governing concept is binary addressing. Each address line carries a binary 0 or 1, so n address lines can represent 2^n distinct addresses. Increasing the number of lines therefore expands the range of main-memory locations that the processor can select. Option A is correct. Address lines do not increase sound, control only a printer, or have no effect; those choices confuse addressing with unrelated output functions.

The governing concept is the control bus, which carries timing and command signals such as read and write. A read signal tells the selected memory or input component that the processor is requesting data; without that signal, the intended read operation is not initiated. Therefore option C is correct. The other options describe unrelated monitor, printer or memory behavior and do not follow from a missing read command.

The governing concept is the CPU register: a very small, very fast storage location inside or immediately associated with the processor. During an instruction cycle, registers can hold the current instruction, an address, operands or an intermediate result for immediate use. Therefore option A is correct. Registers are not designed for personal-file backup, network connection or paper output; those functions belong to storage and peripheral devices.

The governing concept is locality of reference. Temporal locality means that data or instructions used recently are likely to be used again soon; spatial locality means nearby addresses are also likely to be accessed. Cache memory keeps likely-to-be-reused items close to the CPU, reducing average access time. Thus option B is correct. Cache is neither permanent storage nor a printer-only store, and accesses are not equally likely.

The governing concept is the memory hierarchy and a cache miss. If the requested item is absent from cache, the processor or memory system looks in the next lower, larger and slower level, normally main memory; if necessary, storage is consulted through the operating system. Therefore option C is correct. A cache miss does not shut down the computer, involve a printer, or rename a file.

The governing concept is system-level bottleneck analysis. Computer performance is determined by the interaction of the processor, RAM latency and bandwidth, storage, operating system and application behavior. If the processor or storage remains the limiting part, increasing RAM speed improves only one link and cannot produce an equal overall gain. Option D is correct. The other choices either deny RAM’s role, assign speed to the monitor, or make an unsupported claim about software errors.