A letter inside the indicating-light circle in a ladder diagram is used to indicate the color of the switch: the capital letter _______ represents amber (yellow), _______ represents green, _______ represents red, and _______ represents blue.
The color indicated denotes the color of the _________________ lens cover or button on the switch.
A) G; R; A; B; transparent
B) A; G; R; B; transparent
C) R; B; A; G; transparent
D) transparent; A; G; R; B
Share your understanding of this question with the correct explanation.