Final answer:
A Schedule I drug is defined as having no accepted medical use and a high potential for abuse, being classified with the highest restrictions.
Step-by-step explanation:
A Schedule I drug, according to the United States government classification system, is defined as a substance that has no currently accepted medical use and a high potential for abuse. In this classification, drugs are placed into schedules based on their accepted medical use and their potential for abuse or dependency. So, the correct answer to the question "A Schedule I drug is one that the government defines as having" is d) no medical utility and a high potential for abuse.
While psychoactive drugs like cannabis can have medical applications, under federal law, they may still be classified as Schedule I substances, leading to potential legal conflicts, especially as some states have laws that differ from federal regulations. These discrepancies between state and federal law can result in complex legal situations where individuals may face charges for possession or distribution of a substance that is legal within a state but illegal under federal law.