Final answer:
The perception of speakers being more objective, intelligent, and knowledgeable can vary depending on cultural context, with research showing that in some cultures, the expected communication styles of men and women are opposite to American stereotypes. Furthermore, the central route to persuasion requires an analytical and motivated audience, and race and gender have been shown to influence political opinions.
Step-by-step explanation:
The question appears to be related to perceptions of speakers and how they are rated based on various attributes. While the question does not directly provide an answer to which speakers are rated as more objective, intelligent, and knowledgeable, it indirectly relates to concepts in psychology and social studies, particularly those surrounding communication and stereotypes.
Ethnographic research by linguistic anthropologists has demonstrated that speech patterns associated with men and women vary across cultures. In some cultures, contrary to American stereotypes, women are expected to speak more confrontationally, while men are expected to speak more cooperatively.
Regarding the effectiveness of the central route to persuasion, the audience must be analytical and motivated to be persuaded effectively (Option a). Additionally, factors that have been shown to affect an individual's political opinion include race and gender, which are deeply embedded in society and can influence perspectives and attitudes.