What type of circuit is shown below, and how is the output ordinarily connected?

• It is an open-collector gate and is used to drive loads that cannot be connected directly to Vcc due to high noise levels.
• It represents an active-LOW inverter and is used in negative logic systems.
• It is an open-collector gate. An external load must be connected between the output terminal and an appropriate supply voltage.
• Any of the above could be correct, depending on the specific application involved.