You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
University_of_Chicago

Context:
In economics, notable Nobel Memorial Prize in Economic Sciences winners Milton Friedman, a major advisor to Republican U.S. President Ronald Reagan and Conservative British Prime Minister Margaret Thatcher, George Stigler, Nobel laureate and proponent of regulatory capture theory, Gary Becker, an important contributor to the family economics branch of economics, Herbert A. Simon, responsible for the modern interpretation of the concept of organizational decision-making, Paul Samuelson, the first American to win the Nobel Memorial Prize in Economic Sciences, and Eugene Fama, known for his work on portfolio theory, asset pricing and stock market behaviour, are all graduates. American economist, social theorist, political philosopher, and author Thomas Sowell is also an alumnus.

Question:
What British Prime minister advisor is also a university alumni member?

George Stigler