C

1946: ACE (Automatic Computing Engine): Alan Turing presented a detailed paper to the National Physical Laboratory (NPL) Executive Committee, giving the first reasonably complete design of a stored-program computer. However, because of the strict and long-lasting secrecy around his wartime work at Bletchley Park, he was prohibited (having signed the Official Secrets Act) from explaining that he knew that his ideas could be implemented in an electronic device.
 * T  ransition to digital computing  **

1948:SSEM, Small-Scale Experimental Machine or 'Baby' was built at the University of Manchester. It was the first computer to store both its programs and data in RAM, as modern computers do. 1948:The first Curta handheld mechanical calculator is sold. The Curta computed with 11 digits of decimal precision on input operands up to 8 decimal digits. The Curta was about the size of a handheld pepper grinder.

May 6th, 1949:This is considered the birthday of modern computing. Maurice Wilkes and a team at Cambridge University executed the first stored program on the EDSAC computer, which used paper tape input-output. Citation: [] Google.com (Pictures)