Which was the first computer to use transistors instead of vacuum tubes?

Answer: Option A

TRADIC, developed by Bell Labs in 1954, was the first fully transistorized computer in the world.

Before transistors, computers relied on vacuum tubes, which were large, consumed more power, and were less reliable.

TRADIC (Transistorized Airborne Digital Computer) replaced all vacuum tubes with transistors, making it more efficient and compact compared to its predecessors.

Other computers like the IBM-1401 and Datamatic-1000 came later and were among the early commercial machines to use transistors, but they were not the first.

Therefore, TRADIC holds the distinction of being the first computer to use transistors instead of vacuum tubes.