The first truly electronic, general-purpose computer was (A) ENIAC (Electronic Numerical Integrator and Calculator). ENIAC was completed in 1945 and publicly unveiled in 1946. John Mauchly and J. Presper Eckert designed it at the University of Pennsylvania to calculate artillery firing tables for the U.S. Army. It used more than 17,000 vacuum tubes and was much faster than earlier electromechanical computers. This marked the start of the electronic computing era.