In the Practice of Variolation, How Were Patients Exposed to the Smallpox

In the practice of variolation, how were patients exposed to the smallpox pathogen?

A) Babies were nursed by women who had already had smallpox.
B) They were exposed to bedding or clothes of a person with smallpox.
C) They were placed in a room with a person who currently had smallpox.
D) They were exposed to dried scabs from smallpox lesions.
E) They were exposed to a bovine version of the disease, which is mild in humans.