Answer:
The feature that is common to both prose and personal essays is the following one:
a-They both use literary techniques.
Explanation:
Literature is written material of a particular type or subject, and depending on its type (prose, personal essays, poetry, etc.), there are certain rules of style to be followed, all of them belonging to the field of literary techniques. Therefore, when writing either prose or a personal essay, those rules/techniques, which make that particular piece of writing be categorized as the first or the latter, must be followed.