The correct answer is C. Intel Pentium.
The Intel Pentium was the first processor to execute two instructions per cycle. It was released in 1993 and was a major breakthrough in processor technology. The Pentium was able to execute two instructions per cycle by using a technique called superscalar execution. Superscalar execution allows a processor to execute multiple instructions at the same time by breaking them down into smaller steps and then executing those steps in parallel.
The 80486 was a processor that was released in 1989. It was a major upgrade from the 80386, but it could not execute two instructions per cycle. The 80386DX was a processor that was released in 1987. It was an upgrade from the 80386, but it could not execute two instructions per cycle either. The 80386 was a processor that was released in 1985. It was the first 32-bit processor from Intel. It could not execute two instructions per cycle.