Profits made on Revaluation of Assets and Reassessment of Liabilities is distributed among whom?

The correct option is Old Partners.

When a partnership firm is reconstituted—such as during the admission of a new partner, retirement, or death of an existing partner—the assets and liabilities of the firm are revalued to reflect their current market values. This process is recorded in a Revaluation Account (also known as the Profit and Loss Adjustment Account).

Any profit or loss arising from this revaluation represents the change in value that occurred during the period before reconstitution. Since the incoming or newly admitted partner was not part of the firm during this period, they have no claim over these profits, nor are they liable for any losses.
Consequently, the profits or losses made on the revaluation of assets and reassessment of liabilities are distributed strictly among the Old Partners in their old profit-sharing ratio.