B. The opinions may provide clues to the source's feelings and possible bias
Step-by-step explanation:
History helps to unravel the past so as to better understand the present and predict the future to a logical extent.
The primary sources usually gives the eye witness account about an event. The information here is usually original and raw in terms of quality. Some examples are reports of experiments, records, etc. Most facts are usually drawn from primary sources.
Secondary sources are second hand information about an incidence. Most news reports and newspaper accounts are secondary sources of information. They represents opinions about a happening.
Opinions gives investigative and thoughtful perspective about most primary sources of historical data. They provide a keen thought about possible bias and feelings of the actual description of the original evidence.