Answer :
"A shortened, paraphrased version of a text that mentions its key points" would be the proper definition of a summary. Without mentioning the key points, it cannot be a god summary.
The correct answer is A shortened, paraphrased version of a text that mentions its key points.
Indeed, a summary combines direct quotations/citations of the source text for important key points but mostly rewords it in order to shorten it and provide readers with a concise version of it. It is usually used for cataloguing or descriptive purposes but can also be sued to facilitate comprehension and study of the source text.