Quoc: Adobe Illustrator Artwork (AI) is a proprietary file format developed by Adobe Systems for representing single-page vector-based drawings in either the EPS or PDF formats. The. ai filename extension is used by Adobe Illustrator.

Answer this question based on the passage: what is the file extension for adobe illustrator?
HW Chung: OK, some thoughts:
The relevant information is: The. ai filename extension is used by Adobe Illustrator. The answer is . ai.