In computer architecture, the type of bus that connects the major components of a computer system is

Inside a computer, a bus is a set of physical pathways that carry electrical signals between components, and different buses are named according to the scope of what they connect and the kind of signal they carry.

The system bus is the overall collective term for the set of pathways that link the major components of a computer system together, principally the CPU, main memory, and input/output devices. It is described as a "system" bus precisely because its role is to tie together the major building blocks of the whole computer, rather than carrying just one specific kind of signal.

The other buses named are more specialised sub-parts of this overall connection. The address bus carries the memory addresses that specify where data should be read from or written to. The data bus carries the actual data values being transferred between components. The control bus carries the timing and command signals, such as read/write instructions, that coordinate the activity of the other buses. Together, these three specialised buses make up what is collectively referred to as the system bus.

When a question asks which bus connects the "major components" of the whole system in general terms, that phrasing points to system bus, since address, data, and control buses each handle only one specific category of signal.