Step 1: Recognise anandamide as one of the body's own signalling lipids rather than a manufactured drug, and place it in the right receptor family.
Step 2: The molecule binds the same cannabinoid receptors targeted by tetrahydrocannabinol, which is exactly why it is called the bliss molecule. That places it firmly in the cannabinoid category, confirming option (d).
Step 3: Its action is limited because the enzyme fatty acid amide hydrolase rapidly breaks it down, and blocking that enzyme to raise anandamide levels is an active area of drug research.
Step 4: It has no relationship to opioid receptors, casein kinase inhibition or dopamine receptor blockade, so choices (a), (b) and (c) are all irrelevant.
\[\boxed{\text{Cannabinoid neurotransmitter}}\]