Question: At what number largest executive search firm is Claudio Fernández-Aráoz a senior adviser?

Context paragraphs:
Russell Reynolds Associates: Russell Reynolds Associates (RRA) is an executive search firm.  Established in 1969, the firm assists international and domestic companies recruit new leaders and assess business processes.

Executive search: Executive search (informally called headhunting) is a specialized recruitment service which organizations pay to seek out and recruit highly qualified candidates for senior-level and executive jobs (e.g., President, Vice-president, CEO).  Headhunters may also seek out and recruit other highly specialized and/or skilled positions in organizations for which there is strong competition in the job market for the top talent, such as senior data analysts or computer programmers.  The method usually involves commissioning a third-party organization, typically an executive search firm, but possibly a standalone consultant or consulting firm, to research the availability of suitable qualified candidates working for competitors or related businesses or organizations.  Having identified a shortlist of qualified candidates who match the client's requirements, the executive search firm may act as an intermediary to contact the individual(s) and see if they might be interested in moving to a new employer.  The executive search firm may also carry out initial screening of the candidate, negotiations on remuneration and benefits, and preparing the employment contract.

Transearch International: TRANSEARCH International is one of the leading executive search network organisations in the world.  Headquartered in Europe, they have representation in The Americas, Asia Pacific, Europe, Middle East and Africa.  Executive Recruiter News (ERN) currently rates the firm as the 10th largest global executive search firm.  TRANSEARCH International is organized in partner offices by market expertise, business function and geographic location.

Tim McFeeley: Tim McFeeley (born 1946 in Johnstown, New York) is a lawyer and gay activist.  Formerly the Executive Director of the Center for Policy Alternatives (CPA), a progressive political non profit, he is currently a Vice President of national executive search firm Isaacson, Miller.  He joined Isaacson, Miller in 2008 where his practice mainly focuses on the legal, advocacy, and public policy sectors.

Heidrick &amp; Struggles: Heidrick & Struggles International Incorporated is a global executive search firm headquartered in Chicago, Illinois, United States.  In addition to its executive search practice, the firm also has a consulting practice focused on leadership and culture shaping.

Claudio Fernández-Aráoz: Claudio Fernández-Aráoz is an Argentinian author, international speaker and global expert on talent and leadership, ranked by "BusinessWeek" as one of the most influential executive search consultants in the world.  He is currently a senior adviser of Egon Zehnder.  Before joining Egon Zehnder in 1986, he worked at McKinsey & Company in Europe.  He is a frequent lecturer at the Harvard Business School.

Egon Zehnder: Egon Zehnder is a global executive search firm.  Egon Zehnder is the world's third largest executive search and talent strategy firm.  The firm offers services and expertise in the fields of Executive Search, Board Consulting and Leadership Strategy Services.

Howard-Sloan Professional Search: Howard-Sloan Professional Search is a New York-based executive search firm established in 1957.  It is divided into Howard-Sloan Legal Search, Howard-Sloan Financial Search, and Howard-Sloan Professional Search.  In January 2011, "Crain's New York Business" recognized Howard-Sloan Professional Search as one of the New York Area's top 15 largest executive recruiting firms.  Founder and Chairman Emeritus, Stephen H. Berger, was a founding member of the National Association of Legal Search Consultants (NALSC), of which Howard-Sloan Legal Search is a member.

William Vanderbloemen: William Vanderbloemen (born 1969, Taylorsville, North Carolina) is an entrepreneur, pastor, speaker, author, and CEO and Founder of Vanderbloemen Search Group, an executive search firm serving churches, ministries and faith-based organizations.

Stellar Search: Stellar Search and Selection Pvt. Ltd. is an executive search firm (a headhunting /recruitment firm) headquartered in New Delhi and is one of the earliest search firms in the country to offer a specialized Healthcare and Life-science senior talent acquisition service.  The company now provides senior talent acquisition services across diverse industry and has an increasing focus on Gender Diversity hiring.

Supporting paragraphs: Claudio Fernández-Aráoz Egon Zehnder
Answer: third