Where is it forbidden to stop?

Stopping is forbidden in front of fire service access roads because these entrances and routes must always stay clear for emergency vehicles. Even a short stop (for example to let someone out) can block the fire brigade’s access, delay rescue measures, and create danger, so the rule is strict.

Your choice “In front of fire service access roads” is therefore correct.

The other answers are not generally true as stated: a one-way street does not automatically mean you are not allowed to stop; normal stopping/parking rules still apply (you must not block traffic, junctions, crossings, etc.). “Non-parking zone” means parking is forbidden, but brief stopping can still be allowed unless additional signs/markings prohibit it (for example a no-stopping sign or a marked fire service access). A good rule of thumb: anything marked or designated for emergency access must be kept completely free at all times, so you must not stop there at all.