Base value to calculate capital gains 10 yrs after redevelopment of glat

I had a query on what should you consider as the cost of acquisition of a flat that has been redeveloped and sold after 10yrs if living in it.

If the old flat was bought in 1995 at a cost of 34 lakhs and redeveloped and got possession in 2012 and market value of the flat in 2012 is 2 cr.

Now of I sell flat in 2025 for 4 cr then what should I take as base value to calculate capital gains.

Is it 1995 value or 2012 value.

Would help lots of people if you can clarify this.