Which of these buttons is known as a holding contact?

A holding contact is a vital component in control circuits, typically used in conjunction with relays. When a relay is energized, the holding contact maintains the relay's state by allowing the current to continue flowing through the coil, even after the initial activation source is removed. This function is crucial for maintaining continuity in control systems, ensuring that once a relay is activated, it stays on until a reset condition occurs.

In this question, the correct answer highlights the option that represents this concept effectively. The other choices do not illustrate the characteristics of a holding contact, such as being latched or keeping the circuit intact once engaged. Understanding the role of the holding contact is essential for anyone working with electrical control systems, as it directly impacts how various components interact within those systems, ensuring safe and reliable operation.