What is the legal requirement for remote pilots in terms of airspace?

Remote pilots are required to understand airspace classifications because this knowledge is crucial for safe and compliant operations. Different types of airspace (such as controlled, uncontrolled, restricted, and others) have specific regulations and requirements that must be adhered to in order to prevent conflicts with manned aircraft and ensure safety. Understanding these classifications enables remote pilots to determine where they can legally operate their unmanned aircraft, what communications might be necessary, and any airspace-specific restrictions that may apply.

The other options present certain conditions that are either situational or do not represent an outright legal requirement. For instance, flying above 400 feet is a guideline for many operations but does not capture the need for knowledge of the various airspaces. Flying in urban areas and at night also comes with specific regulations but again does not universally apply to all remote pilots. Hence, the requirement to understand airspace classifications is most fundamental for ensuring compliance and safety in all operating environments.