Question: Which global executive search firm is Claudio Fernández-Aráoz a senior adviser of 

Context paragraphs:
IRC Global Executive Search Partners: IRC Global Executive Search Partners (IRC) is an international alliance of retained executive search firms, with more than 80+ offices in 45+ countries, including Europe, the Middle East, the Americas, Africa, Asia and Australia.

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.

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.

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.

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.

HigdonBraddockMatthews: Higdon Partners LLC, headquartered in New York City, is a global executive search firm focused exclusively on the investment management industry.  Clients include large investment management companies, hedge funds, private equity firms, fund of funds, family offices, sovereign wealth funds, endowments, foundations, and corporate plan sponsors.

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.

Charlton Morris: Charlton Morris is a global executive search and selection firm headquartered in Leeds, United Kingdom, that is specialised in the medical devices & technology, life sciences & diagnostics, and industrial markets.  In 2016, Charlton Morris was awarded as the 5th LinkedIn’s Most Socially Engaged Staffing Agencies (specialist boutiques) in the EMEA Region and in 2017 they were awarded Best Executive Search and Selection firm and the Chairman's Award for Business at the Recruitment Business Awards, hosted by The Drum.

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.

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.

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