What is the benefit of passive income through rental properties?

The benefit of passive income through rental properties lies in the ability to earn revenue without needing to engage in daily management and operations. This means that once the property is set up—occupied by tenants—owners can potentially receive a regular income stream with relatively minimal effort. This aligns perfectly with the concept of passive income, where the goal is to generate earnings that don't require constant attention.

In contrast, the other options highlight characteristics or situations connected to rental properties that do not align with the idea of passive income. For instance, requiring day-to-day management tends to imply a more active role, which goes against the essence of passive income. High vacancy risks indicate complications and potential income loss rather than the steady stream of earnings that passive income can provide. Similarly, frequent transactions suggest active engagement and involvement in the real estate market rather than the stability and ease associated with passive income streams. Thus, the answer that emphasizes earnings without active involvement accurately captures the central benefit of rental properties as a source of passive income.