Which of the following electronic technologies is the key technology for making the third-generation electronic computer?

The third generation of electronic computers was built around integrated circuits as the key technology.

An integrated circuit places many transistors together on a single silicon chip, shrinking size and cost.

Vacuum tubes were the first-generation technology, large and unreliable.

Transistors defined the second generation, replacing bulky tubes.

Microprocessors, a whole CPU on one chip, mark the fourth generation.

Integrated circuits sharply improved speed, reliability, and energy use.