Which of the following experiments demonstrates that PrPᶜ is required for prion disease transmission?

A) Mice with the hamster PrP gene are susceptible to hamster prions.
B) Mice lacking the Prp gene are resistant to prion infections.
C) Yeast have proteins that can form self-propagating states like prion proteins.
D) The PrPˢᶜ protein has the same amino acid sequence as the PrPᶜ protein.
E) Injection of brain extracts from kuru patients into monkeys causes the monkeys to get a similar disease.