Final answer:
The phrase 'Laughter is the best medicine' does not have a definitive origin and is considered a proverbial statement. No specific individual from the provided options is credited with coining the phrase, although Norman Cousins wrote extensively about the therapeutic effects of laughter.
Step-by-step explanation:
The phrase "Laughter is the best medicine" does not have a clear attribution to its original source. It is often assumed to be a proverbial statement reflecting a general belief that humor and laughter are beneficial for one's health. This idea has been present in various forms throughout history. For example, Hippocrates, the 'father of Western medicine,' believed in natural causes for diseases, potentially hinting at holistic approaches to health which could include laughter. However, the individuals mentioned in the options, such as Shakespeare, Mark Twain, Norman Cousins, and Dr. Seuss are not credited with originally coining this phrase. In modern times, Norman Cousins wrote about the healing power of laughter in his book 'Anatomy of an Illness,' but he did not originate the saying.