What restriction applies to a large, turbine-powered airplane operating to or from a primary airport in Class B airspace?

A large, turbine-powered airplane operating to or from a primary airport in Class B airspace must operate above the floor when within lateral limits of Class B airspace due to the structured environment and the need to maintain safety and separation among various aircraft types, especially in busy airspace. Class B airspace is designed to facilitate the safe movement of large aircraft, which typically operate at higher altitudes to avoid conflicts with smaller general aviation aircraft that may still be flying lower within the airspace.

When flying within Class B airspace, it is essential that larger, turbine-powered airplanes remain above the designated floor of the Class B airspace to comply with regulations and maintain an orderly flow of air traffic. This restriction helps ensure that the more massive aircraft don't interfere with the operations of smaller aircraft that may be operating at lower altitudes.

In contrast, the other answer choices involve rules or conditions that do not specifically apply to the context of large, turbine-powered airplanes in Class B airspace. While there are speed restrictions and VFR or IFR conditions in place for general operations, the specific requirement to operate above the floor of the Class B airspace is a clear regulation aimed at protecting all aircraft in that crowded environment.