In Bolerio it seems that the purpose of the ostinato is to

a biography is a genre that mainly accounts somebody's life and that is written by somebody else. this genre supports sonia nazario's desire to share enrique's life because she can fully inform readers of his entire emotional journey.

in a biography, an author can share the readers almost everything about a person's life, or just one key event or personal aspect the author is interested in telling, like in this specific case in which sonia nazario is centered in enrique's emotional journey.

you didn't list the options but im guessing it's resolving contradictions

an argumentative essay presents objectively a topic and its main characteristics. besides, it states all this information and facts by giving authentic and substantiated proof to the audience. by contrast, a persuasive text purpose is to convince the audience about some facts by presenting them according to his/her emotions and feelings. the main purpose of a persuasive text is to convince the audience to agree with the author´s opinion. on the other hand, in the argumentative essay, the author leads the writer to recognize his/her point of view as the correct one.

a. beside the fence

explanation: