The correct answer is A. Sources without source qualifiers.
Step-by-step explanation:
In a speech or text, it is important to support major points using credible sources. Besides this, when introducing these sources, it is essential to include source qualifiers that explain the relevance of the source and what makes this credible or the qualifications of this source. This cannot be omitted because the source qualifiers make the source credible and therefore, contribute to the support of your ideas. Thus, to support a point effectively what should not be done is include "sources without source qualifiers".