The four yuga's and the path to Mukhthi.

They are....

Kritha yuga -----In this yuga knowledge and wisdom viz 'Gyana' was the path to Mukhthi.

Dhiredha yuga-----In this yuga-Giving gifts or charity viz 'Dhaana' was the path to mukhthi.

Dwaparayuga-------In this yuga sacrifice viz 'Yagna' was the path to mukhthi

Kaliyuga.-------------In this yuga devotion viz'Bhakth'i is the path to mukhthi