Final answer:
Smallpox can spread from one person to another through direct contact, contact with contaminated objects, and inhalation of respiratory droplets.
Step-by-step explanation:
The correct answer is All of the above. Smallpox can spread from one person to another through direct contact with an infected person's saliva or lesions, contact with contaminated objects, and inhalation of respiratory droplets. These routes of transmission allow the smallpox virus to spread easily from person to person.