Final answer:
People with central roles in social networks influence others through information control rather than through formal authority or coercion. This influence stems from persuasiveness and the ability to shape consensus.
Step-by-step explanation:
People with centrality in social networks can exert influence on others, not by using a formal position of leadership, but through their ability to persuade and build a consensus. Their power lies in their capacity for information control. They are able to persuade by effectively managing and delivering information, rendering options A (silent authority), B (assertiveness) and D (coercion) less relevant in the absence of a formal structure. Therefore, the correct answer to the question is:
C. information control
In the context of the Asch experiment, participants conformed mostly due to normative influences, feeling the pressure to conform to the group norms and expectations, rather than informational influences which refer to accepting information from others as evidence of reality.