Query on execution of sales deed

https://www.lawyersclubindia.com/experts/details.asp?mod_id=223341

From the above link I am clear on the purpose of Agreement for Sale and Sales Deed.

Now, I request your advices on the below scenario -

Agreement of Sale was executed between Builder, Land owner and Purchaser and the same was also registered + Stamp duty up to Rs. 30,000/- had also been paid.

Purchaser had cleared the outstanding total consideration and Builder had also given possession of the flat and had also given possession letter and acknowledged payment made by purchaser by furnishing receipts.

Five years have passed but the Sales Deed has not executed after the above step.

Purchaser resells the flat and also gets a NOC from the Builder and provides the same to the new Purchaser.

My question is - If the Sales deed has to be executed now, between whom should it be executed?

a) between Builder, Land Owner and Original Purchaser OR

b) between Builder, Land Owner and New Purchaser OR

c) between Builder, Land Owner and Both the Original Purchaser along with New Purchaser?

AND

Will Stamp Duty have to be paid, even though Stamp duty was already paid on Agreement of Sale while it was executed earlier?

Note - There were no terms in the Agreement of Sale which indicates that the Agreement of Sale would be treated as Sales Deed once the Builder and Purchaser obliges each other.

Thanks for your valuable advice in advance.

Regards,

Mehul Shah