Agood summary of an informational text must

a. include all the details that the text contains about its subject.
b. state, in the student’s own words, only the most important ideas.
c. evaluate whether the text’s author covered the subject matter well.
d. use phrases and sentences taken directly from the original author.

state, in the student’s own words, only the most important ideas.

B. State, in the student’s own words, only the most important ideas.

Explanation:

A summary must cover the most important elements and points in a long text and it includes anything that is relevant and significant, and must be presented with the student's own words to avoid plagiarism.  

Summaries help readers to gain an overall understanding of a topic and are timesaving techniques.

the type of supporting detail is fact!

i think the anti-race spokesman is working to achieve equality between whites and blacks and to encourage blacks to shakespeare's theory