Which component isolates the stages inside a microprocessor from those outside?

The correct response highlights the function of the bus system in a microprocessor. A bus is a critical component that acts as a communication pathway, allowing data transfer between the various components of a computer system. Specifically, it connects the microprocessor to peripheral devices and memory, effectively isolating the internal stages of the processor from the external components.

The bus carries data, control signals, and addresses, enabling the microprocessor to communicate with RAM, ROM, and other devices without direct interaction with them. This separation is crucial because it ensures that the internal architecture of the microprocessor can function independently of and without interference from external devices. This organization facilitates efficient processing and resource management.

In contrast, buffers serve as temporary storage that can help manage data flow between the processor and external components, but they do not fundamentally isolate the processor's stages. RAM (Random Access Memory) and ROM (Read-Only Memory) are types of storage that hold data and instructions but are not involved in the isolation function between the microprocessor's internal and external elements. Thus, the bus is the component designed specifically for that isolating role.