Which symbol represents a normally open, timed-open (NOTO) contact of a timing relay?

The symbol representing a normally open, timed-open (NOTO) contact of a timing relay is correctly identified as the one that depicts a circle with an "O" shape denoting the open contact and additional lines, arrows, or shapes symbolizing the timing aspect.

In this case, the correct choice illustrates both the open condition of the contact and the characteristic that it remains open for a specific duration after being energized. The circular shape signifies that the contact is normally open until the timing relay is triggered, which aligns it with the functioning of a NOTO contact.

This is critical in understanding how timing relays operate in various electrical circuits, particularly in applications requiring delayed actions. Being familiar with the specific symbols used in circuit diagrams is essential for interpreting and drawing schematic representations accurately.