At the time of retirement of a partner which ratio is calculated?

Gaining ratio

The correct answer is option 2- gaining ratio.

Gaining ratio is calculated at the time of retirement as it the ratio in which the continuing partners have acquired the share from the retiring partner.

At the time of retirement, the new profit sharing ratio among the remaining partners is calculated and so also their gaining ratio.

NOTE- It can be possible that some partner sacrifice due to change in new profit sharing ratio. But gaining ratio is calculated. If it comes in negative then it is considered sacrifice.