Inclusion of only the most important details are included in the effective summary.
Answer: Option C.
Step-by-step explanation:
Summary is the short form of the original text which only consists of the most essential points of the original text. It should tell the crust of the text for which the summary is to be written.
It is very important that the summary of the text is very efficient. For the summary to be efficient, the most important details should be the part of the summary. It should have the summary to communicate the main ideas of the text. The essential facts which are very important only that should be a part of the summary and not any other fact.