A is who (or what) the sentence is about. Is it Noun, Conjunction, Fargment, Pronoun, subject, Linking verb, Adverb, Helping verb, Complex sentence, Preposition, Simple sentence, or Adjective?

in the thematic approach, an interpreter relies on a central theme (i.e., a major point or message) to guide development of a communication activity or device. in presenting the activity or device, the thematic interpreter develops the theme in such a way that it will be highly relevant to an audience.

explanation:

from the political point of view it could be said that the candidate   is an effective speaker because she takes a strong position on the issue. it is an open discussion but probably she is making a presentation and can choose which subjects she wants to address. she is very likely to attain her aim which is to convince voters to accept her proposal.

sorry forgo thte passage

i would believe it would be b., the author wants to draw the reader deeper into the experience