Final answer:
To operate a straight truck with a RGW of 12,000 kg, a Class D license or above is needed. Option C is the correct answer, and a Class D license permits driving vehicles over 11,000 kg of gross weight.
Step-by-step explanation:
To drive a straight truck with commercial plates and a registered gross weight (RGW) of 12,000 kg, the class of license required is Class D or above. Option C, Class D or above, is the correct answer. In many jurisdictions, a Class D license allows the operation of a motor vehicle exceeding 11,000 kilograms (24,000 lbs) in gross weight or registered gross weight, or any combination of motor vehicle not exceeding a total gross weight or registered gross weight of 11,000 kilograms and towed vehicle not exceeding a total gross weight of 4,600 kilograms (10,000 lbs).