According to the Simplified Rational Choice Model, What Does It

According to the simplified rational choice model, what does it mean if an actor is considered unitary?

A) It sees the costs and benefits of an action as canceling each other out.
B) It makes decisions as a single actor, rather than a composite of multiple actors.
C) It does not change its goals or preferences.
D) It does not consider the behavior of other actors before making a decision.