For Greece Category B car theory, which statement about regulatory signs is correct?

1. Circular red-bordered signs normally give restrictions or prohibitions, such as no entry, no parking, speed limits, or no overtaking.
2. The safest answer about regulatory signs is to ignore the usual priority rule.
3. The correct response for regulatory signs is mainly to use the horn and continue.
4. This topic concerns only vehicle comfort and has no safety or legal effect.