Ka is the correct answer.
The ancient egyptians were all about preserving their essence for the afterlife. In ancient religion, Ka was a principal aspect of the soul of a human being or of a god. Egyptians believed that their ka was able to inhabit their corpses and live on afterlife. The belief on Ka led people to believe that mummification was necessary in order to maitain the body of the deceased person intact, if one didn't take the necessary steps then they would cease to exist after death.