Question: The Tower Commission had a National Security Advisor who had served in what previous capacity?

Context paragraphs:
Deputy National Security Advisor (United States): The Deputy Assistant to the President for National Security Affairs, also known as the Deputy National Security Advisor, is a member of the Executive Office of the President of the United States and the United States National Security Council, serving as deputy to the President's National Security Advisor.

Thomas E. Donilon: Thomas E. "Tom" Donilon (born May 14, 1955) is an American lawyer and former government official who served as National Security Advisor in the Obama administration.  Previously, he served together with diplomat Wendy Sherman as Agency Review Team Lead for the State Department in the Obama transition, and as Deputy to National Security Advisor James Jones early in the Obama administration.  Donilon replaced Jones as National Security Advisor on October 8, 2010.

National Security Advisor (India): The National Security Advisor (NSA) is the chief executive of the National Security Council (NSC), and the primary advisor to the Prime Minister of India on national and international security.  It is the National Security Advisor to whom intelligence agencies such as the Research and Analysis Wing and Intelligence Bureau report, rather than directly to the Prime Minister.  Due to such vested powers, NSA is a prominent and powerful office in the bureaucracy.  All the NSAs appointed since the inception of the post belong to the Indian Foreign Service except M K Narayanan and the incumbent, Ajit Doval, who belong to the Indian Police Service.

National Security Advisor (Nigeria): The National Security Advisor is a senior aide in the cabinet of the President of Nigeria who serves as the chief advisor to the President on national security issues.  He participates in the meetings of the National Security Council and other deliberations on security matters.  The National Security Advisor is often appointed by the President of Nigeria and serve a tenure not more than 4 years.

Brent Scowcroft: Brent Scowcroft ( ; born March 19, 1925) is a retired United States Air Force lieutenant general who was the United States National Security Advisor under U.S. Presidents Gerald Ford and George H. W. Bush.  He also served as Military Assistant to President Richard Nixon and as Deputy Assistant to the President for National Security Affairs in the Nixon and Ford administrations.  He served as Chairman of the President's Foreign Intelligence Advisory Board under President George W. Bush from 2001 to 2005 and assisted President Barack Obama in choosing his national security team.

Stephen Hadley: Stephen John Hadley (born February 13, 1947) was the 21st U.S. Assistant to the President for National Security Affairs (commonly referred as National Security Advisor), serving under President George W. Bush during the second term of his administration.  Hadley was Deputy National Security Advisor during the Bush's first term.  Before that Hadley served in a variety of capacities in the defense and national security fields.  He has also worked as a lawyer and consultant in private practice.

National Security Advisor (United States): The Assistant to the President for National Security Affairs (APNSA), commonly referred to as the National Security Advisor (NSA) or at times informally termed the NSC advisor, is a senior aide in the Executive Office of the President, based at the West Wing of the White House, who serves as the chief in-house advisor to the President of the United States on national security issues.  The National Security Advisor is appointed by the President and does not require confirmation by the Senate, but an appointment of a three or four-star general to the role requires Senate reconfirmation of military rank.

Tower Commission: The Tower Commission was commissioned on 1 December 1986 by U.S. President Ronald Reagan in response to the Iran Contra scandal.  Reagan appointed Republican and former Senator John Tower of Texas, former Secretary of State Edmund Muskie, and former National Security Advisor Brent Scowcroft.

Faryar Shirzad: Faryar Shirzad (in Persian: فریار شیرزاد‎ ‎ ); born 1965 in London formerly served on the staff of the National Security Council at the White House from March 2003 through August 2006, first as a special assistant to the President for International Economic Affairs, and then as deputy assistant to the President and deputy national security advisor for International Economic Affairs.  In those roles, Shirzad was responsible for advising the President, the National Security Advisor and the Director of the National Economic Council on all international economic policy matters, including trade, investment, finance, development, energy and environment.  He also served as the President’s personal representative to the G-8 (the “G8 Sherpa”), and led the preparations for the President’s participation in other international economic summits, such as the U.S.-E.U. Summit, the Asia Pacific Economic Cooperation Forum and the Summit of the Americas.

Homeland Security Advisor: The Assistant to the President for Homeland Security and Counterterrorism, commonly referred to as the Homeland Security Advisor and occasionally holding the title of Deputy National Security Advisor for Homeland Security and Counterterrorism, is a senior aide in the Executive Office of the President, based in the West Wing of the White House, who serves as the chief in-house advisor to the President of the United States on homeland security and counterterrorism issues.  The Homeland Security Advisor is a statutory member of the Homeland Security Council.  Serving at the pleasure of the President, the Homeland Security Advisor does not require Senate confirmation for appointment to the office.

Supporting paragraphs: Tower Commission Brent Scowcroft
Answer: United States Air Force lieutenant general