The central purpose of this passage is to describe the process for entering the afterlife in ancient Egyptian culture. It explains how both the body and soul needed to be preserved and supported in preparation for the journey through the afterlife, which would include traveling to the Hall of Truth. The passage mentions the process of mummification as well as the use of spells from the Book of the Dead to support the soul. The funeral is also discussed as marking the transition from the world of the living to the land of the dead. Therefore, the correct answer is option B: to describe the process for entering the afterlife.