When you come to a STOP sign, you should:

Answer: D — Stop completely, then go when safe

When you come to a STOP sign, you must always come to a complete stop. This means that you must make sure your vehicle is completely stopped before entering the intersection or crosswalk. Option A, stopping quickly and then driving on, is incorrect because you may not have enough time to assess the intersection for safety. Option B, reducing speed but proceeding without stopping, is incorrect because it does not meet the requirement of a complete stop. Option C, stopping and then starting, is incorrect because the word "start" suggests that you do not need to fully stop before moving again. Thus, the best option is to always come to a complete stop at a STOP sign and then proceed when it is safe to do so.