Definition: You are given a question on virology. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: The current testing policy of the Centers for Disease Control and the World Health Organization is:
(A)“Opt-in” (B)“Opt-out” (C)Mandatory testing of prisoners (D)Mandatory testing of high-risk groups

B