Answer:
d. Mainframes came before minicomputers, which led to the development of microcomputers.
Explanation:
The first <em>mainframe</em> was introduced in 1951: The UNIVAC (UNIVersal Automatic Computer I): large computer systems, for general purpose, with hundreds of users (separated from the computer) and fast computations, typically deployed by large business, industry, and government organizations.
The <em>minicomputers</em> are another class of computers that start to evolve since the late of the 1950s and the beginning of 1960s (like LINC, PDP-1, among many others), and focused on to have a more direct contact with the user or programmer, and because of this, it is said that minicomputers were the first 'personal' computers. They were cheaper than mainframes and with less memory capacity.
Finally, the <em>microcomputers</em> appeared around the beginning of 1970s (Micral), and sometime later (Altair 8800, Apple II) and were firstly used by hobbyists and computers enthusiasts. The term microcomputers have been supplanted nowadays by 'personal computers'.
