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:
Boston

Context:
Boston's colleges and universities have a significant effect on the regional economy. Boston attracts more than 350,000 college students from around the world, who contribute more than $4.8 billion annually to the city's economy. The area's schools are major employers and attract industries to the city and surrounding region. The city is home to a number of technology companies and is a hub for biotechnology, with the Milken Institute rating Boston as the top life sciences cluster in the country. Boston receives the highest absolute amount of annual funding from the National Institutes of Health of all cities in the United States.

Question:
The Milken Institute rated Boston as the top what in the country?

life sciences cluster