Definition: You are given a question on high school psychology. 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: Which of the following conditions best characterizes the focus of a behavioral model of school intervention?
(A)Underlying psychological processes (B)Relationships among children (C)Events during the child's infancy (D)Observable events

D