Studies of the Pluralist Model Within Distinct Communities,such as Dahl's

Studies of the pluralist model within distinct communities,such as Dahl's work in New Haven,have which important limitation?

A) They are not scientific because they lack effective controls.
B) Racial and ethnic minorities are largely absent from such studies.
C) Observation is necessarily limited to local elites who belong to a larger national ruling class.
D) They fail to address the potential of elites keeping certain matters out of government debate.