At least inches of free conductor, measured from the point in the box where it emerges from its raceway or cable sheath, must be left at each outlet, junction, or switch point for the connection of luminaires or devices.

150mm

Explanation:

The correct answer to the given question is 150mm or 6 inch.

Atleast 150mm or 6 inches of a free conductor, measured from the point in box where it emerges from its cable sheath or raceway, must be left at each outlet, switch or junction point to lumination or connection of devices.

150mm of free conductor is required for the devices to be connected, this needs to be placed in the junctions