The correct answer is B. 8080.
The Intel 8080 is a 8-bit microprocessor chip that was first released in 1974. It was the first microprocessor to be widely used in personal computers, and it was used in the Altair 8800, which is considered to be the first real personal computer.
The 6502 is a 8-bit microprocessor chip that was first released in 1975. It was used in the Apple II, Commodore 64, and many other popular home computers.
The 6400 is a family of microprocessor chips that was released by Intel in 1972. It was the first microprocessor chip to be used in a commercial product, the Datapoint 2200.
The 8286 is a 16-bit microprocessor chip that was released by Intel in 1982. It was used in the IBM PC and many other personal computers.