The correct answer is: C. 80286
The IBM PC AT was released in 1984 and was a significant upgrade to the original IBM PC. It featured a 286-based processor, which was twice as fast as the 8088 processor in the original PC. The PC AT also had a larger amount of memory and a faster hard drive.
The 80387 is a math coprocessor that was released in 1987. It was designed to speed up floating-point calculations. The 8088 is a 16-bit microprocessor that was released in 1981. It was the processor in the original IBM PC. The 8086 is a 16-bit microprocessor that was released in 1978. It was the processor in the IBM PC XT.
The 80286 is a 16-bit microprocessor that was released in 1982. It was the processor in the IBM PC AT. It was twice as fast as the 8088 processor in the original PC and had a larger amount of memory and a faster hard drive.