Which Best Describes the Role of Neurotransmitters in Behavior

Which best describes the role of neurotransmitters in behavior?

A) In specific ecological contexts,neurotransmitters can be important for behavior.For instance,aggression requires the neurotransmitter serotonin.
B) Some specific behaviors will require neurotransmitters.For instance,aggression requires the neurotransmitter serotonin.
C) Neurotransmitters allow neurons to communicate,and are thus involved in all behaviors.Levels of specific neurotransmitters have been associated with levels of specific behaviors -- such as serotonin and aggression.
D) Neurotransmitters have been developed for researchers who want to manipulate animal behaviors.For instance,serotonin can be applied to lobsters to increase aggression.