Best format to import file from Civil 3D software into Rhinoceros

Dear
I was using the csv data and imported them into the Rhinoceros software to create a NURBS surface, but at this time I have a drone data and I am using the Civil 3D software to create surface using the method “Kriging” or “NoFilter” in the Civil 3D and I want to export the surface into the Rhinoceros software to create a NURBS surface and import it into the Plaxis (Bentley) software as a Numerical solution software.
1- What is the best way to import a surface created by the methods “Kriging” or “NoFilter” from the Civil 3D software into the Rhinoceros software?

2- What is the best format to be imported?

3- Should I use the “Extract solid from surface” option in the Civil 3D and then after that I import it into the Rhinoceros or I could just select the surface and without converting to solid, I save it as a dxf or other format and just import it into the Rhinoceros software to use the NURBS surface option?

I would be thankful if you may guide me in this process
Thanks for your response
Sincerely
Amir Farshadfar