Refer to the drawing of a valve motor control circuit for a valve that is currently fully closed (see figure below).
Note: Limit switch (LS) contacts are shown open regardless of valve position, but relay contacts are shown open/closed according to the standard convention for control circuit drawings.
Which one of the following describes when the motor-operated valve will begin to stroke open?
A. At the same time the alarm actuates.
B. 10 seconds after PB2 is depressed.
C. Immediately after PB2 is depressed.
D. Immediately after PB1 is depressed if contact #1 is closed.
Share your understanding of this question with the correct explanation.