A Manitoba Class 3 and higher licence is acceptable as a Commercial Driver's Licence (CDL) in the United States. For operation under the U.S. Federal Highway Administration (FHWA), you must be at least _____ years of age and carry a completed medical card.

Answer: B — twenty-one

A Manitoba Class 3 and higher licence is acceptable as a Commercial Driver's Licence (CDL) in the United States. However, to operate under the U.S. Federal Highway Administration (FHWA), you must be at least twenty-one years of age and carry a completed medical card. Option A, eighteen years, is incorrect because it does not meet the minimum age requirement of twenty-one. Option C, twenty-five years, is incorrect because it is above the minimum age requirement. Option D, twenty years, is also incorrect because it is below the minimum age requirement and does not account for carrying a completed medical card. Therefore, B is the correct answer.