Official portable versions of AutoCAD Civil 3D are not offered by

Stay safe.
— A civil CAD admin

Recommendations

The term verified is largely a marketing gimmick used by repackers to differentiate their release from obviously broken ones. It does not mean "safe for engineering work" nor "compliant with industry standards."

You can access a simplified version of AutoCAD in any web browser. While it doesn't support the full Civil 3D toolset (like pipe networks or pressure parts), it allows for viewing, editing, and measuring Civil 3D objects. Autodesk Drive/Desktop Connector: