Which investment type is considered a basic category of real estate investment?

Commercial property is indeed a basic category of real estate investment because it encompasses real estate assets that are used primarily for business purposes. This includes office buildings, retail spaces, warehouses, and industrial facilities. Investing in commercial property can yield rental income and potential capital appreciation.

The other options do not fall under the category of real estate investment: peer-to-peer lending involves lending money to individuals or businesses through online platforms, cryptocurrency investments are focused on digital currencies and blockchain technology, and startup equity involves investing directly in the ownership of new businesses or companies. These options represent alternative investment vehicles that do not pertain directly to physical real estate assets.