Final answer:
The primary reason to participate in the underground economy is to avoid taxes, which is characteristic of markets and labour operating outside government regulations and oversight. Option A is correct .
Step-by-step explanation:
The main reason to participate in the underground economy is to avoid taxes. The underground economy is made up of labor and goods that operate outside of official government oversight, regulatory systems, or human protections. This economy does not adhere to regulations, and hence, participants do not pay taxes.
This may provide a semblance of economic relief to individuals, especially in heavily regulated economies where these underground markets flourish. For example, from street vendors in Mexico City to unlicensed cab drivers in New York, all of them make transactions without government approval to avoid taxes and regulations.