According to the Law of the Republic of Armenia "On Ensuring Road Traffic Safety", a certificate of the right to drive "D" category and "D1" sub-category vehicles can be issued to persons who have:
Driving license of "B" or "C" category or "C1" sub-category vehicles and they have reached 21 years of age.✓Correct answer
They have a driver's license for driving "B" category or "B1" sub- category vehicles and have reached 18 years of age.
Driver's license of "AB" category or "A1B1" sub-categories and they have reached 18 years of age.
B or "C" category or "C1" sub-category driving license and they are 20 years old.
Explanation
Eligibility for a D-category or D1 driving certificate requires both a prior B, C, or C1 entitlement and attainment of age 21. The alternatives based on age 18, age 20, or unrelated licence combinations fail at least one of those requirements.