Research Conducted During the Run-Up to President Obama's Election Demonstrates

Research conducted during the run-up to President Obama's election demonstrates that

A) one exception to the negative stereotypes about African Americans is not sufficient to reduce bias.
B) prior to the election,President Obama's candidacy alone was enough to produce sharp reductions in bias against blacks.
C) only after the election of President Obama did bias against blacks start to decline.
D) President Obama's candidacy-but not his election-increased bias against blacks.