Marc Andreessen — Education: B.S. in Computer Science, University of Illinois at Urbana-Champaign

NoteThe source directly confirms the claim. The Wikipedia article states that Marc Andreessen received a B.S. (bachelor's degree) in computer science from the University of Illinois at Urbana-Champaign. The source also confirms the additional context that he co-developed Mosaic while working at NCSA (National Center for Supercomputing Applications) at the University of Illinois. All elements of the claim are verified by the source text.