What illustrator native file format preserves all illustrator data?

The native file format that preserves all Illustrator data is the Illustrator file format itself, which has the extension ".ai". However, among the options provided, the most suitable choice would be EPS.

EPS (Encapsulated PostScript) files are designed to work within many different design applications, allowing for a broad range of compatibility while retaining essential Illustrator data. The EPS format can store vector graphics as well as information about the appearance of the images. It is ideal for ensuring that vector art created in Illustrator maintains its quality and fidelity when opened in other applications.

The other options, while useful in their own contexts, do not preserve all Illustrator data as effectively. TIFF is primarily a raster format, PDF can compress and alter file data, and PNG is also a raster format that does not support the complex vector data and layers found in Illustrator files. Each of these formats serves specific purposes, but EPS remains relevant for sharing Illustrator data with other software while maintaining quality.