Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: (CNN) Senate intelligence committee Chairman Richard Burr shut down a line of questioning from California Sen. Kamala Harris at Wednesday's high-profile hearing, admonishing her and other Democrats to stop cutting off witnesses. The move rankled some on Twitter who argued the North Carolina Republican was singling out Harris, one of three women on the intelligence panel, during Wednesday's contentious hearing. Harris was pressing Deputy Attorney General Rod Rosenstein over whether he would sign a letter to give Special Counsel Robert Mueller full independence from the Justice Department in his probe, which would have the same effect as a letter issued for then-Special Counsel Patrick Fitzgerald in the investigation into the 2003 leaking of then-covert CIA officer Valerie Plame's identity.Sen. Kamala Harris grilled deputy Attorney General Rod Rosenstein at a hearing WednesdayThe exchange prompted Republican senators to stop interrupting 
 Question:"Mr. Chairman, respectfully, I would point out that this witness has joked, as we all have, his ability to filibuster," _ argued, before Burr stopped her again.

Kamala Harris