About Priority vehicle: blue light + siren, both together: which statement is WRONG?
Only police, fire brigade, and ambulance can be a priority vehicle.
Causing danger (for example by driving through a red light) to give way to a priority vehicle is not allowed; you look for a safe way to make room.
The same AND-requirement applies the other way: a siren without a blue beacon (e.g. during a test) does not yet make a vehicle a priority vehicle.
Requires BOTH signals at the same time: blue light AND two-tone siren.
Explanation
trap: only-the-well-known-three. Book p.116 also names 'other emergency service vehicles and Rijkswaterstaat'; the status depends on the signals (blue light + two-tone siren together), not on the organisation