According to InterNACHI's Standards of Practice, how many residential units can be inspected?

The Standards of Practice set by InterNACHI specify that a home inspector may inspect residential units that are designed for four or fewer families. This includes single-family homes, duplexes, triplexes, and fourplexes. The designation of "four" is crucial as it delineates the boundary between what is considered residential and what typically falls under commercial or multi-family property inspections.

By understanding this, one can see that units designed for five or more families generally do not fall within the guidelines for a typical residential inspection as outlined by InterNACHI. This is because such properties often require additional expertise and standards that differ from those applied to smaller residential properties. Thus, the correct answer reflects the regulatory framework that governs home inspections for residential units.