Final answer:
The minimum distance conductors on the exterior surfaces must be supported from adjacent surfaces is 150 mm, ensuring electrical safety and preventing accidental contacts or electrical arcing.
Step-by-step explanation:
The question asks about the minimum distance conductors on exterior surfaces must be supported from adjacent surfaces. The correct answer to this question is A) 150 mm. Conductors, when installed on the exterior surfaces of structures, must be supported by brackets, racks, or insulators, and must maintain a certain distance from adjacent surfaces to ensure electrical safety and prevent accidental contacts or electrical arcing. The spacing ensures that there is sufficient air insulation to resist any potential electrical discharge that may occur at the conductor's voltage level.