Answer:
The correct answer is the software that they produced for PC´s. Both companies began developing OS software that were very much alike. Initially, Apple did not design, or create, these softwares, and much less the interfaces with graphics. But it soon became an issue between the two companies that had once shared almost a common goal.
Step-by-step explanation:
The entire love-hate relationship between Bill Gates´ Microsoft and Steve Jobs´ Apple began in the 70´s, during the PC initial era, and then the first love part came in the 80´s when Jobs developed the first Macintosh and Gates did the same for the software for it. The two companies seemed to be seeing eye to eye, and Microsoft had its objectives set on earning their share from the sales of Macintosh. However, this changed rapidly after 1983, when Jobs himself began to also develop software. At that point, the Apple software and the Windows 1.0, took off in different directions and the two companies began to compete furiously with one another. In fact, at some point, Jobs accused Gates of having created the Windows 1.0 program from stolen ideas.