Step 3 » GENERAL learning environment Category Tr

For answers  A  and  B 

You are obliged to drive at a speed not exceeding 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 where visibility is smaller than 50 meters.

For answer  C 

In the areas where performing the overtaking maneuver is prohibited, driving at a speed not exceeding 30 km/h in the urban area is not imposed.

Recommendations:

Reducing speed and maximum speed limits - Audio-Video lesson --> Road Traffic Code - Travel speed

For answers  A  and  B 

Regulation** - Article 123

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

For answer  C 

The traffic legislation does not provide anything in this respect.

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