A 22-meter sailing vessel propelled by machinery must display what during daylight?

A 22-meter sailing vessel that is equipped with machinery and is being propelled by that machinery is considered a power-driven vessel under the rules. During daylight, such vessels are required to display a black cone, the appropriate day shape for a power-driven vessel that is also sailing.

The black cone is an indication that the vessel is not only sailing but is also using its engine for propulsion, which distinguishes it from sailing vessels that are being propelled solely by their sails. The day shapes serve to communicate the vessel's status to other mariners, thereby enhancing safety on the water.

In contrast, the other options—like a white light, red flag, or green light—do not correspond to the requirements for a vessel under these specific circumstances. Each of these lights or flags serves different purposes under different conditions, but they are not applicable in this context when identifying a powering sailing vessel during daylight.