Step 3 » GENERAL learning environment Category Tr

The circulation on the lane reserved for the public transport of persons, signalled as such, is permitted to the vehicles that perform public transport of persons, these having the obligation to circulate only on this lane, as long as such a lane is found on the route on which they circulate.

Also, on the lane reserved for the public transport of persons, signalled as such, the circulation of the motor vehicles with priority circulation regime is also permitted, when they move in intervention actions or in missions that have an emergency character. The circulation of the other vehicles on such lanes is prohibited.

The correct answer is: A

You can find here video lesson with The direction and the lane of circulation --> Road Traffic Code - The direction and the lane of circulation

Recommendations:

The complete explanation of the sign --> Mandatory road for the category of vehicles

Lanes of circulation with special destination - Audio-Video Lesson --> Road Traffic Code - The direction and the lane of circulation

OUG* - Article 43

(1) If a road is provided with a lane intended for slow vehicles or for the public transport of persons, signalled as such, these will circulate only on the respective lane.
[...]

Regulation** - Article 104

The vehicles that perform public transport of persons are driven on the lane reserved for them, if such a lane exists and is signalled as such. On the same lane may also circulate the motor vehicles with priority circulation regime when they move in intervention actions or in missions that have an emergency character.

* OUG = GOVERNMENT EMERGENCY ORDINANCE no. 195 from December 12, 2002 updated (Road Traffic Code)
** Regulation = REGULATION for the application of OUG 195/2002 updated (Road Traffic Code Regulation)