Computers have evolved from early mainframes to relatively small smart devices with high computing power. Which of the following inventions contributed to reducing the physical size of computers?

Integrated circuits pack thousands of transistors onto a single small chip, which is what let computers shrink from room-sized machines to handheld devices.

The vacuum tube belonged to the first generation and was large, hot and fragile, making early computers enormous.

Registers are tiny storage locations inside the processor, not an invention that reduced the overall size of a computer.

Solid state memory stores data compactly but did not itself drive the shrinking of the whole machine.

Placing many components on one chip cut wiring, power and space dramatically.

The progression from vacuum tubes to transistors to integrated circuits marks the main generations of computer hardware.