Answer:
I believe this is the definition of A. subject-by-subject organization.
Explanation:
When writing compare and contrast essays, some types of organization are commonly used. The subject-by-subject organization uses different paragraphs to develop each subject. In one paragraph, all the details of the first subject are addressed. In the next paragraph, all the details of the second subject are addressed. They are each addressed in their totality, separately.
That is different, for example, from the point-by-point organization. In this case, both subjects have a detail addressed in the same paragraph. Then the next paragraph addresses another detail, again about both subjects.
I believe we can safely say that, when the essay "explains the topic sentence by first discussing all the details on one subject then all the details on the other subject", it is employing the subject-by-subject organization.
