What does the phrase "usual pattern of behavior" mean?

A) Behavior characterizes how most people respond to a given situation.
B) A person reports that she or he experiences the same emotions most of the time.
C) Behavior is regulated by brain activity and genetic tendencies.
D) A person acts consistently across time or across situations.

"Usual pattern of behavior" refers to the consistency in a person's actions and reactions across different situations and over time. This implies that a person tends to behave in a certain way that is predictable and consistent, which can be observed and documented. Hence, option D accurately captures the meaning of the phrase. The other choices are not fully relevant because they do not directly relate to the consistency and predictability of behavior that is implied in the phrase.