Final answer:
Neuropeptide Y triggers cravings for c) carbohydrates. It is a neurotransmitter that is part of a larger group of molecules known as neuropeptides, which play roles in hunger regulation within the brain.
Step-by-step explanation:
The brain chemical, neuropeptide Y, is known to cause cravings for carbohydrates. Neuropeptides, like neuropeptide Y, are neurotransmitter molecules composed of chains of amino acids and are involved in signaling across synapses in the brain. They can also function as hormones in other body systems. Neuropeptide Y specifically plays a role in regulating hunger and is associated with the stimulation of carbohydrate intake when you are hungry. Foods rich in carbohydrates tend to be less effective at promoting satiety compared to those rich in fatty acids, which may contribute to the persistent cravings experienced when levels of neuropeptide Y are elevated.