Which of the following indicates when turbulence is present?

AIRMET Tango is specifically used to advise pilots of moderate turbulence, which includes both turbulent air and clear air turbulence associated with atmospheric conditions like strong winds or thermal activity. This alert is crucial for flight safety, as it provides information that can significantly affect flight operations and passenger comfort.

In contrast, AIRMET Sierra pertains to IFR conditions due to reduced visibility and ceilings, while AIRMET Zulu addresses icing conditions in flight. AIRMET Delta is not an official designation; thus, it does not apply. Understanding the purpose of each AIRMET type helps pilots anticipate and respond to changing weather phenomena during their flights.