Which instruments are connected to the pitot-static system?

The pitot-static system is a critical part of an aircraft's instrumentation, primarily responsible for measuring parameters related to airspeed and altitude. The correct choice highlights the instruments that utilize the pressure information from this system.

The airspeed indicator uses dynamic pressure from the pitot tube to display the aircraft's speed relative to the surrounding air, while the altimeter operates based on static pressure to provide altitude above sea level. The vertical speed indicator also relies on static pressure changes to indicate the rate of climb or descent of the aircraft.

In contrast, the other choices include instruments that either do not use the pitot-static system or rely on other principles. The turn coordinator, for example, measures the rate of turn using gyroscopic principles rather than pressure changes, making it unrelated to the pitot-static system. Hence, the instruments identified in the correct choice are specifically those linked to pressure measurements, marking them as integral to the functioning of the pitot-static system.