Questions: Which is an example of an investment in physical capital? Maria saves 1 million for retirement. The government builds a new highway to downtown. Starbucks reimburses its employees for college tuition expenses. You buy stock in Microsoft.

The answer is: The government builds a new highway to downtown.

Explanation for each option:

1. Maria saves $1 million for retirement.
   This is not an investment in physical capital. Saving money for retirement is a form of financial investment or personal savings, not an investment in physical capital, which involves tangible assets.

2. The government builds a new highway to downtown.
   This is an example of an investment in physical capital. Physical capital refers to tangible assets that are used in the production of goods and services, such as buildings, machinery, and infrastructure. A highway is a form of infrastructure that facilitates transportation and economic activity.

3. Starbucks reimburses its employees for college tuition expenses.
   This is not an investment in physical capital. It is an investment in human capital, as it enhances the skills and education of employees, which can improve productivity and efficiency.

4. You buy stock in Microsoft.
   This is a financial investment, not an investment in physical capital. Buying stock represents ownership in a company and is a way to invest in financial markets, rather than in tangible assets.