If a group of words is not a complete sentence, it is a

fragment
complete sentence
topic sentence

c. is the answer to your question.

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.