Who built the world's first electronic calculator using telephone relays, light bulbs and batteries?

Answer: Option C

George Stibitz made the original version of this in 1936 on his kitchen table, hence the name “Model K”. Using scrapped relays from Bell Labs and strips of metal from a tin can, it can add two binary digits. In November 1937, George Stibitz, then working at Bell Labs (1930 - 1941), completed a relay-based calculator he later dubbed the “Model K” (for “kitchen table”, on which he had assembled it), which calculated using binary addition.