Step 3 » GENERAL learning environment Category B (B, B1)

For answer  A  and  B 

You are obliged to drive with a speed that does not exceed 30 km/h in the urban area or 50 km/h outside built-up area, in the particularly dangerous curves signalled as such or in the curves in which the visibility is smaller than 50 meters.

For answer  C 

In the areas in which performing the overtaking maneuver is prohibited, the driving with a speed that does not exceed 30 km/h in the urban area is not imposed.

Recommendations:

Speed reduction and maximum speed limits - Audio-Video Lesson --> Road Traffic Code - Travel speed

For answer  A  and  B 

Regulation** - Article 123

The driver of a vehicle is obliged to drive with a speed that does not exceed 30 km/h in the urban areas or 50 km/h outside built-up areas, in the following situations:
[...]
b) in particularly dangerous curves signalled as such or in which the visibility is smaller than 50 m;
[...]

For answer  C 

The road legislation does not provide anything in this regard.

** Regulation = REGULATION for the implementation of OUG 195/2002 updated (Road Traffic Code Regulation)