Final answer:
Dolphins have been found to emit a "chirp" that is related to positive emotions and is similar to laughter.
Step-by-step explanation:
The correct answer is b) Dolphins. Dolphins have been found to emit a "chirp" that is thought to be stimulated by positive emotions and is related to laughter. Dolphins communicate with each other using a wide variety of vocalizations, and their chirping sounds are one example of their vocal repertoire.