Anubis opened the mummies’ mouths. Why?

The correct answer is A so they could breathe.

In ancient Egyptian belief, the opening of the mouth ceremony was performed to allow the deceased to breathe in the afterlife. This ritual was believed to enable the mummy to speak, eat, and drink, essentially preparing them for their journey in the next world. If you have more questions about mummification or ancient Egyptian practices, feel free to ask!