About Lighting and reflection of the trailer: which statement is WRONG?

The red TRIANGULAR reflectors belong at the REAR; at the front are white (non-triangular) retroreflectors.
This trailer itself must always have a rear fog light.
✓ Every trailer must have a reversing light.
White retroreflectors belong at the FRONT; at the rear are red triangular reflectors.

Correct answer: Every trailer must have a reversing light.

Explanation

A reversing light (white or yellow) is required only if the permitted maximum mass exceeds 750 kg.

The red TRIANGULAR reflectors belong at the REAR; at the front are white (non-triangular) retroreflectors.
This trailer itself must always have a rear fog light. The only exception is if the TOWING vehicle itself has no fog light. The law does contain a date nuance for older heavy trailers, but the exam follows the book: treat the rear fog light as always mandatory.
White retroreflectors belong at the FRONT; at the rear are red triangular reflectors. Red rear, white front.