Answer:
A. Low levels of education on the part of people of color who don't know when to seek services.
Step-by-step explanation:
Lower educational attainment is in part to blame for the underutilization of healthcare services on the part of people of color. As the question explains, many undereducated people of color do not know when to seek medical service, for what conditions to do so, or where.
Another important reason is that people of color in the U.S. are on average poorer, and many of them do not have any health insurance at all, making medical services too expensive.