About Agricultural vehicles, riders and livestock: which statement is WRONG?

The book literally names two classes: some agricultural vehicles at most 25 km/u, others at most 40 km/u.
The rule asks for BOTH: adjusting your speed AND passing with ample sideways distance (1.5 m), precisely to avoid startling the animals.
✓ You can rely on the indicator signal of an agricultural vehicle, just like with an ordinary car.
Behind a tractor with a high-loaded trailer you know one thing for certain: the driver does not see you.

Correct answer: You can rely on the indicator signal of an agricultural vehicle, just like with an ordinary car.

Explanation

With agricultural traffic, lighting, indicators and brake lights do not always work; do not blindly assume the vehicle will do what it signals

The book literally names two classes: some agricultural vehicles at most 25 km/u, others at most 40 km/u. You cannot read the speed of the vehicle ahead off the label 'tractor' alone
The rule asks for BOTH: adjusting your speed AND passing with ample sideways distance (1.5 m), precisely to avoid startling the animals
Behind a tractor with a high-loaded trailer you know one thing for certain: the driver does not see you. The book therefore explicitly says: wait patiently until there is free space to overtake — a short gap is not free space