Given the task definition and input, reply with output. In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Question: Where was the headquarters of Investigative Group International when she worked for them? Passage:Seidman was born on August 24, 1955 to a Jewish family, the daughter of Eileen Joan (nee Ladenson) and Frank Seidman. She received a B.A. from Miami University and a J.D. from the University of Georgia School of Law. After school, she worked as a senior investigator for the investigation firm, Investigative Group International and later for the People for the American Way. She then worked an assistant to Senator Ted Kennedy and chief investigator for the Senate Labor and Human Resources Committee where she worked against the Robert Bork (1987) and Clarence Thomas (1990) nominations to the U.S. Supreme Court. Nan Aron from Alliance for Justice asserts that she was the one that tipped Seidman off about Thomas' alleged harassment. In 1991, she prepped Anita Hill before she testified.
Links: a. Terry Lenzner b. Terry Lenzner c. United States Senate Committee on Health, Education, Labor and Pensions d. American Jews
a