The correct answer is: D. 386DX
The 386DX was the first Intel chip to support a 32-bit bus architecture. It was released in 1985 and was a major upgrade over the previous 286 chip. The 386DX had a clock speed of up to 33 MHz and could address up to 4GB of memory. It was also the first Intel chip to support virtual memory, which allowed it to run multiple programs at the same time.
The 486SI was released in 1989 and was a 32-bit chip, but it did not support a 32-bit bus architecture. The Pentium was released in 1993 and was a 64-bit chip. The 286 was released in 1982 and was a 16-bit chip.
The 386DX was a major upgrade over the previous 286 chip. It was the first Intel chip to support a 32-bit bus architecture, which allowed it to access more memory and run faster. It was also the first Intel chip to support virtual memory, which allowed it to run multiple programs at the same time. The 386DX was a very successful chip and was used in many different types of computers, including personal computers, workstations, and servers.