Question: Which software developed by Pito Salas was purchased by IBM in the 1990's?
Sentence (from "Lotus Software"): Lotus is most commonly known for the Lotus 1-2-3 spreadsheet application, the first feature-heavy, user-friendly, reliable and WYSIWYG-enabled product to become widely available in the early days of the IBM PC, when there was no graphical user interface.
Relevant evidence: No