Identifying Inhibitory Neurotransmitters in Neural Communication

In the context of neural communication, consider the role of neurotransmitters in synaptic transmission. When a neuron is activated by an incoming signal, it produces an action potential that travels down its axon. Upon reaching the axon terminals, the action potential triggers the release of neurotransmitters into the synaptic cleft. Which of the following neurotransmitters is primarily associated with the inhibition of post-synaptic neurons, leading to reduced neuronal excitability and is often linked with calming and anxiolytic effects?